Take-Home Points

• The authors have developed a total shoulder glenoid prosthesis that conforms with the humeral head in its center and is nonconforming on its peripheral edge.
• All clinical survey and range of motion parameters demonstrated statistically significant improvements at final follow-up.
• Only 3 shoulders (1.7%) required revision surgery.
• Eighty-six (63%) of 136 shoulders demonstrated no radiographic evidence of glenoid loosening.
• This is the first and largest study that evaluates the clinical and radiographic outcomes of this hybrid shoulder prosthesis.

Fixation of the glenoid component is the limiting factor in modern total shoulder arthroplasty (TSA). Glenoid loosening, the most common long-term complication, necessitates revision in up to 12% of patients.^1-4 By contrast, humeral component loosening is relatively uncommon, affecting as few as 0.34% of patients.⁵ Multiple long-term studies have found consistently high rates (45%-93%) of radiolucencies around the glenoid component.^3,6,7 Although their clinical significance has been debated, radiolucencies around the glenoid component raise concern about progressive loss of fixation.

Since TSA was introduced in the 1970s, complications with the glenoid component have been addressed with 2 different designs: conforming (congruent) and nonconforming. In a congruent articulation, the radii of curvature of the glenoid and humeral head components are identical, whereas they differ in a nonconforming model. Joint conformity is inversely related to glenohumeral translation.⁸ Neer’s original TSA was made congruent in order to limit translation and maximize the contact area. However, this design results in edge loading and a so-called rocking-horse phenomenon, which may lead to glenoid loosening.^9-13 Surgeons therefore have increasingly turned to nonconforming implants. In the nonconforming design, the radius of curvature of the humeral head is smaller than that of the glenoid. Although this design may reduce edge loading,¹⁴ it allows more translation and reduces the relative contact area of the glenohumeral joint. As a result, more contact stress is transmitted to the glenoid component, leading to polyethylene deformation and wear.^15,16

Dual radii of curvature are designed to augment joint stability without increasing component wear. Biomechanical data have indicated that edge loading is not increased by having a central conforming region added to a nonconforming model.¹⁷ The clinical value of this prosthesis, however, has not been determined. Therefore, we conducted a study to describe the intermediate-term clinical and radiographic outcomes of TSAs that use a novel hybrid glenoid component.

Materials and Methods

This study was approved (protocol AAAD3473) by the Institutional Review Board of Columbia University and was conducted in compliance with Health Insurance Portability and Accountability Act (HIPAA) regulations.

Patient Selection

At Columbia University Medical Center, Dr. Bigliani performed 196 TSAs with a hybrid glenoid component (Bigliani-Flatow; Zimmer Biomet) in 169 patients between September 1998 and November 2007. All patients had received a diagnosis of primary glenohumeral arthritis as defined by Neer.¹⁸ Patients with previous surgery such as rotator cuff repair or subacromial decompression were included in our review, and patients with a nonprimary form of arthritis, such as rheumatoid, posttraumatic, or post-capsulorrhaphy arthritis, were excluded.

Operative Technique

For all surgeries, Dr. Bigliani performed a subscapularis tenotomy with regional anesthesia and a standard deltopectoral approach. A partial anterior capsulectomy was performed to increase the glenoid’s visibility. The inferior labrum was removed with a needle-tip bovie while the axillary nerve was being protected with a metal finger or narrow Darrach retractor. After reaming and trialing, the final glenoid component was cemented into place. Cement was placed only in the peg or keel holes and pressurized twice before final implantation. Of the 196 glenoid components, 168 (86%) were pegged and 28 (14%) keeled; in addition,190 of these components were all-polyethylene, whereas 6 had trabecular-metal backing. All glenoid components incorporated the hybrid design of dual radii of curvature. After the glenoid was cemented, the final humeral component was placed in 30° of retroversion. Whenever posterior wear was found, retroversion was reduced by 5° to 10°. The humeral prosthesis was cemented in cases (104/196, 53%) of poor bone quality or a large canal.

After surgery, the patient’s sling was fitted with an abduction pillow and a swathe, to be worn the first 24 hours, and the arm was passively ranged. Patients typically were discharged on postoperative day 2. Then, for 2 weeks, they followed an assisted passive range of motion (ROM) protocol, with limited external rotation, for promotion of subscapularis healing.

Clinical Outcomes

Dr. Bigliani assessed preoperative ROM in all planes. During initial evaluation, patients completed a questionnaire that consisted of the 36-Item Short Form Health Survey^19,20 (SF-36) and the American Shoulder and Elbow Surgeons²¹ (ASES) and Simple Shoulder Test²² (SST) surveys. Postoperative clinical data were collected from office follow-up visits, survey questionnaires, or both. Postoperative office data included ROM, subscapularis integrity testing (belly-press or lift-off), and any complications. Patients with <1 year of office follow-up were excluded. In addition, the same survey questionnaire that was used before surgery was mailed to all patients after surgery; then, for anyone who did not respond by mail, we attempted contact by telephone. Neer criteria were based on patients’ subjective assessment of each arm on a 3-point Likert scale (1 = very satisfied, 2 = satisfied, 3 = dissatisfied). Patients were also asked about any specific complications or revision operations since their index procedure.

Physical examination and office follow-up data were obtained for 129 patients (148/196 shoulders, 76% follow-up) at a mean of 3.7 years (range 1.0-10.2 years) after surgery. Surveys were completed by 117 patients (139/196 shoulders, 71% follow-up) at a mean of 5.1 years (range, 1.6-11.2 years) after surgery. Only 15 patients had neither 1 year of office follow-up nor a completed questionnaire. The remaining 154 patients (178/196 shoulders, 91% follow-up) had clinical follow-up with office, mail, or telephone questionnaire at a mean of 4.8 years (range, 1.0-11.2 years) after surgery. This cohort of patients was used to determine rates of surgical revisions, subscapularis tears, dislocations, and other complications.

Radiographic Outcomes

Patients were included in the radiographic analysis if they had a shoulder radiograph at least 1 year after surgery. One hundred nineteen patients (136/196 shoulders, 69% follow-up) had radiographic follow-up at a mean of 3.7 years (range, 1.0-9.4 years) after surgery.

Statistical Analysis

Statistical analysis was performed with Stata Version 10.0. Paired t tests were used to compare preoperative and postoperative numerical data, including ROM and survey scores. We calculated 95% confidence intervals (CIs) and set statistical significance at P < .05. For qualitative measures, the Fisher exact test was used. Survivorship analysis was performed according to the Kaplan-Meier method, with right-censored data for no event or missing data.²⁵

Results

Clinical Analysis of Demographics

In demographics, the clinical and radiographic patient subgroups were similar to each other and to the overall study population (Table 2). Of 196 patients overall, 16 (8%) had a concomitant rotator cuff repair, and 27 (14%) underwent staged bilateral shoulder arthroplasties.

Clinical Analysis of ROM and Survey Scores

Operative shoulder ROM in forward elevation, external rotation at side, external rotation in abduction, and internal rotation all showed statistically significant (P < .001) improvement from before surgery to after surgery. Over 3.7 years, mean (SD) forward elevation improved from 107.3° (34.8°) to 159.0° (29.4°), external rotation at side improved from 20.4° (16.7°) to 49.4° (11.3°), and external rotation in abduction improved from 53.7° (24.3°) to 84.7° (9.1°). Internal rotation improved from a mean (SD) vertebral level of S1 (6.0 levels) to T9 (3.7 levels).

All validated survey scores also showed statistically significant (P < .001) improvement from before surgery to after surgery. Over 5.1 years, mean (SD) SF-36 scores improved from 64.9 (13.4) to 73.6 (17.1), ASES scores improved from 41.1 (22.5) to 82.7 (17.7), SST scores improved from 3.9 (2.8) to 9.7 (2.2), and visual analog scale pain scores improved from 5.6 (3.2) to 1.4 (2.1). Of 139 patients with follow-up, 130 (93.5%) were either satisfied or very satisfied with their TSA, and only 119 (86%) were either satisfied or very satisfied with the nonoperative shoulder.

Clinical Analysis of Postoperative Complications

Of the 178 shoulders evaluated for complications, 3 (1.7%) underwent revision surgery. Mean time to revision was 2.3 years (range, 1.5-3.9 years). Two revisions involved the glenoid component, and the third involved the humerus. In one of the glenoid cases, a 77-year-old woman fell and sustained a fracture at the base of the trabecular metal glenoid pegs; her component was revised to an all-polyethylene component, and she had no further complications. In the other glenoid case, a 73-year-old man’s all-polyethylene component loosened after 2 years and was revised to a trabecular metal implant, which loosened as well and was later converted to a hemiarthroplasty. In the humeral case, a 33-year-old man had his 4-year-old index TSA revised to a cemented stem and had no further complications.

Table 4 compares the clinical and radiographic outcomes of patients who required subscapularis repair, capsular shift, or implant revision with the outcomes of all other study patients, and Figure 3 shows Kaplan-Meier survivorship.

Postoperative Radiographic Analysis

Glenoid Component. At a mean of 3.7 years (minimum, 1 year) after surgery, 86 (63%) of 136 radiographically evaluated shoulders showed no glenoid lucencies; the other 50 (37%) showed ≥1 lucency. Of the 136 shoulders, 33 (24%) had a Lazarus score of 1, 15 (11%) had a score of 2, and only 2 (2%) had a score of 3. None of the shoulders had a score of 4 or 5.

Humeral Component. Of the 136 shoulders, 91 (67%) showed no lucencies in any of the 8 humeral stem zones; the other 45 (33%) showed 1 to 3 lucencies. Thirty (22%) of the 136 shoulders had 1 stem lucency zone, 8 (6%) had 2, and 3 (2%) had 3. None of the shoulders had >3 periprosthetic zones with lucent lines.

Discussion

In this article, we describe a hybrid glenoid TSA component with dual radii of curvature. Its central portion is congruent with the humeral head, and its peripheral portion is noncongruent and larger. The most significant finding of our study is the low rate (1.1%) of glenoid component revision 4.8 years after surgery. This rate is the lowest that has been reported in a study of ≥100 patients. Overall implant survival appeared as an almost flat Kaplan-Meir curve. We attribute this low revision rate to improved biomechanics with the hybrid glenoid design. 

Symptomatic glenoid component loosening is the most common TSA complication.^1,26-28 In a review of 73 Neer TSAs, Cofield7 found glenoid radiolucencies in 71% of patients 3.8 years after surgery. Radiographic evidence of loosening, defined as component migration, or tilt, or a circumferential lucency 1.5 mm thick, was present in another 11% of patients, and 4.1% developed symptomatic loosening that required glenoid revision. In a study with 12.2-year follow-up, Torchia and colleagues³ found rates of 84% for glenoid radiolucencies, 44% for radiographic loosening, and 5.6% for symptomatic loosening that required revision. In a systematic review of studies with follow-up of ≥10 years, Bohsali and colleagues²⁷ found similar lucency and radiographic loosening rates and a 7% glenoid revision rate. These data suggest glenoid radiolucencies may progress to component loosening.

Degree of joint congruence is a key factor in glenoid loosening. Neer’s congruent design increases the contact area with concentric loading and reduces glenohumeral translation, which leads to reduced polyethylene wear and improved joint stability. In extreme arm positions, however, humeral head subluxation results in edge loading and a glenoid rocking-horse effect.^{9-13,17,29-31} Conversely, nonconforming implants allow increased glenohumeral translation without edge loading,¹⁴ though they also reduce the relative glenohumeral contact area and thus transmit more contact stress to the glenoid.^16,17 A hybrid glenoid component with central conforming and peripheral nonconforming zones may reduce the rocking-horse effect while maximizing ROM and joint stability. Wang and colleagues32 studied the biomechanical properties of this glenoid design and found that the addition of a central conforming region did not increase edge loading.

Additional results from our study support the efficacy of a hybrid glenoid component. Patients’ clinical outcomes improved significantly. At 5.1 years after surgery, 93.5% of patients were satisfied or very satisfied with their procedure and reported less satisfaction (86%) with the nonoperative shoulder. Also significant was the reduced number of radiolucencies. At 3.7 years after surgery, the overall percentage of shoulders with ≥1 glenoid radiolucency was 37%, considerably lower than the 82% reported by Cofield7 and the rates in more recent studies.^3,16,33-36 Of the 178 shoulders in our study, 10 (5.6%) had subscapularis tears, and 6 (3.4%) of 178 had these tears surgically repaired. This 3.4% compares favorably with the 5.9% (of 119 patients) found by Miller and colleagues37 28 months after surgery. Of our 178 shoulders, 27 (15.2%) had clinically significant postoperative complications; 18 (10.1%) of the 178 had these complications surgically treated, and 9 (5.1%) had them managed nonoperatively. Bohsali and colleagues²⁷ systematically reviewed 33 TSA studies and found a slightly higher complication rate (16.3%) 5.3 years after surgery. Furthermore, in our study, the 11 patients who underwent revision, capsular shift, or subscapularis repair had final outcomes comparable to those of the rest of our study population.

Our study had several potential weaknesses. First, its minimum clinical and radiographic follow-up was 1 year, whereas most long-term TSA series set a minimum of 2 years. We used 1 year because this was the first clinical study of the hybrid glenoid component design, and we wanted to maximize its sample size by reporting on intermediate-length outcomes. Even so, 93% (166/178) of our clinical patients and 83% (113/136) of our radiographic patients have had ≥2 years of follow-up, and we continue to follow all study patients for long-term outcomes. Another weakness of the study was its lack of a uniform group of patients with all the office, survey, complications, and radiographic data. Our retrospective study design made it difficult to obtain such a group without significantly reducing the sample size, so we divided patients into 4 data groups. A third potential weakness was the study’s variable method for collecting complications data. Rates of complications in the 178 shoulders were calculated from either office evaluation or patient self-report by mail or telephone. This data collection method is subject to recall bias, but mail and telephone contact was needed so the study would capture the large number of patients who had traveled to our institution for their surgery or had since moved away. Fourth, belly-press and lift-off tests were used in part to assess subscapularis function, but recent literature suggests post-TSA subscapularis assessment can be unreliable.³⁸ These tests may be positive in up to two-thirds of patients after 2 years.³⁹ Fifth, the generalizability of our findings to diagnoses such as rheumatoid and posttraumatic arthritis is limited. We had to restrict the study to patients with primary glenohumeral arthritis in order to minimize confounders.

This study’s main strength is its description of the clinical and radiographic outcomes of using a single prosthetic system in operations performed by a single surgeon in a large number of patients. This was the first and largest study evaluating the clinical and radiographic outcomes of this hybrid glenoid implant. Excluding patients with nonprimary arthritis allowed us to minimize potential confounding factors that affect patient outcomes. In conclusion, our study results showed the favorable clinical and radiographic outcomes of TSAs that have a hybrid glenoid component with dual radii of curvature. At a mean of 3.7 years after surgery, 63% of patients had no glenoid lucencies, and, at a mean of 4.8 years, only 1.7% of patients required revision. We continue to follow these patients to obtain long-term results of this innovative prosthesis.

Take-Home Points

• The authors have developed a total shoulder glenoid prosthesis that conforms with the humeral head in its center and is nonconforming on its peripheral edge.
• All clinical survey and range of motion parameters demonstrated statistically significant improvements at final follow-up.
• Only 3 shoulders (1.7%) required revision surgery.
• Eighty-six (63%) of 136 shoulders demonstrated no radiographic evidence of glenoid loosening.
• This is the first and largest study that evaluates the clinical and radiographic outcomes of this hybrid shoulder prosthesis.

Fixation of the glenoid component is the limiting factor in modern total shoulder arthroplasty (TSA). Glenoid loosening, the most common long-term complication, necessitates revision in up to 12% of patients.^1-4 By contrast, humeral component loosening is relatively uncommon, affecting as few as 0.34% of patients.⁵ Multiple long-term studies have found consistently high rates (45%-93%) of radiolucencies around the glenoid component.^3,6,7 Although their clinical significance has been debated, radiolucencies around the glenoid component raise concern about progressive loss of fixation.

Since TSA was introduced in the 1970s, complications with the glenoid component have been addressed with 2 different designs: conforming (congruent) and nonconforming. In a congruent articulation, the radii of curvature of the glenoid and humeral head components are identical, whereas they differ in a nonconforming model. Joint conformity is inversely related to glenohumeral translation.⁸ Neer’s original TSA was made congruent in order to limit translation and maximize the contact area. However, this design results in edge loading and a so-called rocking-horse phenomenon, which may lead to glenoid loosening.^9-13 Surgeons therefore have increasingly turned to nonconforming implants. In the nonconforming design, the radius of curvature of the humeral head is smaller than that of the glenoid. Although this design may reduce edge loading,¹⁴ it allows more translation and reduces the relative contact area of the glenohumeral joint. As a result, more contact stress is transmitted to the glenoid component, leading to polyethylene deformation and wear.^15,16

Dual radii of curvature are designed to augment joint stability without increasing component wear. Biomechanical data have indicated that edge loading is not increased by having a central conforming region added to a nonconforming model.¹⁷ The clinical value of this prosthesis, however, has not been determined. Therefore, we conducted a study to describe the intermediate-term clinical and radiographic outcomes of TSAs that use a novel hybrid glenoid component.

Materials and Methods

This study was approved (protocol AAAD3473) by the Institutional Review Board of Columbia University and was conducted in compliance with Health Insurance Portability and Accountability Act (HIPAA) regulations.

Patient Selection

At Columbia University Medical Center, Dr. Bigliani performed 196 TSAs with a hybrid glenoid component (Bigliani-Flatow; Zimmer Biomet) in 169 patients between September 1998 and November 2007. All patients had received a diagnosis of primary glenohumeral arthritis as defined by Neer.¹⁸ Patients with previous surgery such as rotator cuff repair or subacromial decompression were included in our review, and patients with a nonprimary form of arthritis, such as rheumatoid, posttraumatic, or post-capsulorrhaphy arthritis, were excluded.

Operative Technique

For all surgeries, Dr. Bigliani performed a subscapularis tenotomy with regional anesthesia and a standard deltopectoral approach. A partial anterior capsulectomy was performed to increase the glenoid’s visibility. The inferior labrum was removed with a needle-tip bovie while the axillary nerve was being protected with a metal finger or narrow Darrach retractor. After reaming and trialing, the final glenoid component was cemented into place. Cement was placed only in the peg or keel holes and pressurized twice before final implantation. Of the 196 glenoid components, 168 (86%) were pegged and 28 (14%) keeled; in addition,190 of these components were all-polyethylene, whereas 6 had trabecular-metal backing. All glenoid components incorporated the hybrid design of dual radii of curvature. After the glenoid was cemented, the final humeral component was placed in 30° of retroversion. Whenever posterior wear was found, retroversion was reduced by 5° to 10°. The humeral prosthesis was cemented in cases (104/196, 53%) of poor bone quality or a large canal.

After surgery, the patient’s sling was fitted with an abduction pillow and a swathe, to be worn the first 24 hours, and the arm was passively ranged. Patients typically were discharged on postoperative day 2. Then, for 2 weeks, they followed an assisted passive range of motion (ROM) protocol, with limited external rotation, for promotion of subscapularis healing.

Clinical Outcomes

Dr. Bigliani assessed preoperative ROM in all planes. During initial evaluation, patients completed a questionnaire that consisted of the 36-Item Short Form Health Survey^19,20 (SF-36) and the American Shoulder and Elbow Surgeons²¹ (ASES) and Simple Shoulder Test²² (SST) surveys. Postoperative clinical data were collected from office follow-up visits, survey questionnaires, or both. Postoperative office data included ROM, subscapularis integrity testing (belly-press or lift-off), and any complications. Patients with <1 year of office follow-up were excluded. In addition, the same survey questionnaire that was used before surgery was mailed to all patients after surgery; then, for anyone who did not respond by mail, we attempted contact by telephone. Neer criteria were based on patients’ subjective assessment of each arm on a 3-point Likert scale (1 = very satisfied, 2 = satisfied, 3 = dissatisfied). Patients were also asked about any specific complications or revision operations since their index procedure.

Physical examination and office follow-up data were obtained for 129 patients (148/196 shoulders, 76% follow-up) at a mean of 3.7 years (range 1.0-10.2 years) after surgery. Surveys were completed by 117 patients (139/196 shoulders, 71% follow-up) at a mean of 5.1 years (range, 1.6-11.2 years) after surgery. Only 15 patients had neither 1 year of office follow-up nor a completed questionnaire. The remaining 154 patients (178/196 shoulders, 91% follow-up) had clinical follow-up with office, mail, or telephone questionnaire at a mean of 4.8 years (range, 1.0-11.2 years) after surgery. This cohort of patients was used to determine rates of surgical revisions, subscapularis tears, dislocations, and other complications.

Radiographic Outcomes

Patients were included in the radiographic analysis if they had a shoulder radiograph at least 1 year after surgery. One hundred nineteen patients (136/196 shoulders, 69% follow-up) had radiographic follow-up at a mean of 3.7 years (range, 1.0-9.4 years) after surgery.

Statistical Analysis

Statistical analysis was performed with Stata Version 10.0. Paired t tests were used to compare preoperative and postoperative numerical data, including ROM and survey scores. We calculated 95% confidence intervals (CIs) and set statistical significance at P < .05. For qualitative measures, the Fisher exact test was used. Survivorship analysis was performed according to the Kaplan-Meier method, with right-censored data for no event or missing data.²⁵

Results

Clinical Analysis of Demographics

In demographics, the clinical and radiographic patient subgroups were similar to each other and to the overall study population (Table 2). Of 196 patients overall, 16 (8%) had a concomitant rotator cuff repair, and 27 (14%) underwent staged bilateral shoulder arthroplasties.

Clinical Analysis of ROM and Survey Scores

Operative shoulder ROM in forward elevation, external rotation at side, external rotation in abduction, and internal rotation all showed statistically significant (P < .001) improvement from before surgery to after surgery. Over 3.7 years, mean (SD) forward elevation improved from 107.3° (34.8°) to 159.0° (29.4°), external rotation at side improved from 20.4° (16.7°) to 49.4° (11.3°), and external rotation in abduction improved from 53.7° (24.3°) to 84.7° (9.1°). Internal rotation improved from a mean (SD) vertebral level of S1 (6.0 levels) to T9 (3.7 levels).

All validated survey scores also showed statistically significant (P < .001) improvement from before surgery to after surgery. Over 5.1 years, mean (SD) SF-36 scores improved from 64.9 (13.4) to 73.6 (17.1), ASES scores improved from 41.1 (22.5) to 82.7 (17.7), SST scores improved from 3.9 (2.8) to 9.7 (2.2), and visual analog scale pain scores improved from 5.6 (3.2) to 1.4 (2.1). Of 139 patients with follow-up, 130 (93.5%) were either satisfied or very satisfied with their TSA, and only 119 (86%) were either satisfied or very satisfied with the nonoperative shoulder.

Clinical Analysis of Postoperative Complications

Of the 178 shoulders evaluated for complications, 3 (1.7%) underwent revision surgery. Mean time to revision was 2.3 years (range, 1.5-3.9 years). Two revisions involved the glenoid component, and the third involved the humerus. In one of the glenoid cases, a 77-year-old woman fell and sustained a fracture at the base of the trabecular metal glenoid pegs; her component was revised to an all-polyethylene component, and she had no further complications. In the other glenoid case, a 73-year-old man’s all-polyethylene component loosened after 2 years and was revised to a trabecular metal implant, which loosened as well and was later converted to a hemiarthroplasty. In the humeral case, a 33-year-old man had his 4-year-old index TSA revised to a cemented stem and had no further complications.

Table 4 compares the clinical and radiographic outcomes of patients who required subscapularis repair, capsular shift, or implant revision with the outcomes of all other study patients, and Figure 3 shows Kaplan-Meier survivorship.

Postoperative Radiographic Analysis

Glenoid Component. At a mean of 3.7 years (minimum, 1 year) after surgery, 86 (63%) of 136 radiographically evaluated shoulders showed no glenoid lucencies; the other 50 (37%) showed ≥1 lucency. Of the 136 shoulders, 33 (24%) had a Lazarus score of 1, 15 (11%) had a score of 2, and only 2 (2%) had a score of 3. None of the shoulders had a score of 4 or 5.

Humeral Component. Of the 136 shoulders, 91 (67%) showed no lucencies in any of the 8 humeral stem zones; the other 45 (33%) showed 1 to 3 lucencies. Thirty (22%) of the 136 shoulders had 1 stem lucency zone, 8 (6%) had 2, and 3 (2%) had 3. None of the shoulders had >3 periprosthetic zones with lucent lines.

Discussion

In this article, we describe a hybrid glenoid TSA component with dual radii of curvature. Its central portion is congruent with the humeral head, and its peripheral portion is noncongruent and larger. The most significant finding of our study is the low rate (1.1%) of glenoid component revision 4.8 years after surgery. This rate is the lowest that has been reported in a study of ≥100 patients. Overall implant survival appeared as an almost flat Kaplan-Meir curve. We attribute this low revision rate to improved biomechanics with the hybrid glenoid design. 

Symptomatic glenoid component loosening is the most common TSA complication.^1,26-28 In a review of 73 Neer TSAs, Cofield7 found glenoid radiolucencies in 71% of patients 3.8 years after surgery. Radiographic evidence of loosening, defined as component migration, or tilt, or a circumferential lucency 1.5 mm thick, was present in another 11% of patients, and 4.1% developed symptomatic loosening that required glenoid revision. In a study with 12.2-year follow-up, Torchia and colleagues³ found rates of 84% for glenoid radiolucencies, 44% for radiographic loosening, and 5.6% for symptomatic loosening that required revision. In a systematic review of studies with follow-up of ≥10 years, Bohsali and colleagues²⁷ found similar lucency and radiographic loosening rates and a 7% glenoid revision rate. These data suggest glenoid radiolucencies may progress to component loosening.

Degree of joint congruence is a key factor in glenoid loosening. Neer’s congruent design increases the contact area with concentric loading and reduces glenohumeral translation, which leads to reduced polyethylene wear and improved joint stability. In extreme arm positions, however, humeral head subluxation results in edge loading and a glenoid rocking-horse effect.^{9-13,17,29-31} Conversely, nonconforming implants allow increased glenohumeral translation without edge loading,¹⁴ though they also reduce the relative glenohumeral contact area and thus transmit more contact stress to the glenoid.^16,17 A hybrid glenoid component with central conforming and peripheral nonconforming zones may reduce the rocking-horse effect while maximizing ROM and joint stability. Wang and colleagues32 studied the biomechanical properties of this glenoid design and found that the addition of a central conforming region did not increase edge loading.

Additional results from our study support the efficacy of a hybrid glenoid component. Patients’ clinical outcomes improved significantly. At 5.1 years after surgery, 93.5% of patients were satisfied or very satisfied with their procedure and reported less satisfaction (86%) with the nonoperative shoulder. Also significant was the reduced number of radiolucencies. At 3.7 years after surgery, the overall percentage of shoulders with ≥1 glenoid radiolucency was 37%, considerably lower than the 82% reported by Cofield7 and the rates in more recent studies.^3,16,33-36 Of the 178 shoulders in our study, 10 (5.6%) had subscapularis tears, and 6 (3.4%) of 178 had these tears surgically repaired. This 3.4% compares favorably with the 5.9% (of 119 patients) found by Miller and colleagues37 28 months after surgery. Of our 178 shoulders, 27 (15.2%) had clinically significant postoperative complications; 18 (10.1%) of the 178 had these complications surgically treated, and 9 (5.1%) had them managed nonoperatively. Bohsali and colleagues²⁷ systematically reviewed 33 TSA studies and found a slightly higher complication rate (16.3%) 5.3 years after surgery. Furthermore, in our study, the 11 patients who underwent revision, capsular shift, or subscapularis repair had final outcomes comparable to those of the rest of our study population.

Our study had several potential weaknesses. First, its minimum clinical and radiographic follow-up was 1 year, whereas most long-term TSA series set a minimum of 2 years. We used 1 year because this was the first clinical study of the hybrid glenoid component design, and we wanted to maximize its sample size by reporting on intermediate-length outcomes. Even so, 93% (166/178) of our clinical patients and 83% (113/136) of our radiographic patients have had ≥2 years of follow-up, and we continue to follow all study patients for long-term outcomes. Another weakness of the study was its lack of a uniform group of patients with all the office, survey, complications, and radiographic data. Our retrospective study design made it difficult to obtain such a group without significantly reducing the sample size, so we divided patients into 4 data groups. A third potential weakness was the study’s variable method for collecting complications data. Rates of complications in the 178 shoulders were calculated from either office evaluation or patient self-report by mail or telephone. This data collection method is subject to recall bias, but mail and telephone contact was needed so the study would capture the large number of patients who had traveled to our institution for their surgery or had since moved away. Fourth, belly-press and lift-off tests were used in part to assess subscapularis function, but recent literature suggests post-TSA subscapularis assessment can be unreliable.³⁸ These tests may be positive in up to two-thirds of patients after 2 years.³⁹ Fifth, the generalizability of our findings to diagnoses such as rheumatoid and posttraumatic arthritis is limited. We had to restrict the study to patients with primary glenohumeral arthritis in order to minimize confounders.

This study’s main strength is its description of the clinical and radiographic outcomes of using a single prosthetic system in operations performed by a single surgeon in a large number of patients. This was the first and largest study evaluating the clinical and radiographic outcomes of this hybrid glenoid implant. Excluding patients with nonprimary arthritis allowed us to minimize potential confounding factors that affect patient outcomes. In conclusion, our study results showed the favorable clinical and radiographic outcomes of TSAs that have a hybrid glenoid component with dual radii of curvature. At a mean of 3.7 years after surgery, 63% of patients had no glenoid lucencies, and, at a mean of 4.8 years, only 1.7% of patients required revision. We continue to follow these patients to obtain long-term results of this innovative prosthesis.

Take-Home Points

• The authors have developed a total shoulder glenoid prosthesis that conforms with the humeral head in its center and is nonconforming on its peripheral edge.
• All clinical survey and range of motion parameters demonstrated statistically significant improvements at final follow-up.
• Only 3 shoulders (1.7%) required revision surgery.
• Eighty-six (63%) of 136 shoulders demonstrated no radiographic evidence of glenoid loosening.
• This is the first and largest study that evaluates the clinical and radiographic outcomes of this hybrid shoulder prosthesis.

Fixation of the glenoid component is the limiting factor in modern total shoulder arthroplasty (TSA). Glenoid loosening, the most common long-term complication, necessitates revision in up to 12% of patients.^1-4 By contrast, humeral component loosening is relatively uncommon, affecting as few as 0.34% of patients.⁵ Multiple long-term studies have found consistently high rates (45%-93%) of radiolucencies around the glenoid component.^3,6,7 Although their clinical significance has been debated, radiolucencies around the glenoid component raise concern about progressive loss of fixation.

Since TSA was introduced in the 1970s, complications with the glenoid component have been addressed with 2 different designs: conforming (congruent) and nonconforming. In a congruent articulation, the radii of curvature of the glenoid and humeral head components are identical, whereas they differ in a nonconforming model. Joint conformity is inversely related to glenohumeral translation.⁸ Neer’s original TSA was made congruent in order to limit translation and maximize the contact area. However, this design results in edge loading and a so-called rocking-horse phenomenon, which may lead to glenoid loosening.^9-13 Surgeons therefore have increasingly turned to nonconforming implants. In the nonconforming design, the radius of curvature of the humeral head is smaller than that of the glenoid. Although this design may reduce edge loading,¹⁴ it allows more translation and reduces the relative contact area of the glenohumeral joint. As a result, more contact stress is transmitted to the glenoid component, leading to polyethylene deformation and wear.^15,16

Dual radii of curvature are designed to augment joint stability without increasing component wear. Biomechanical data have indicated that edge loading is not increased by having a central conforming region added to a nonconforming model.¹⁷ The clinical value of this prosthesis, however, has not been determined. Therefore, we conducted a study to describe the intermediate-term clinical and radiographic outcomes of TSAs that use a novel hybrid glenoid component.

Materials and Methods

This study was approved (protocol AAAD3473) by the Institutional Review Board of Columbia University and was conducted in compliance with Health Insurance Portability and Accountability Act (HIPAA) regulations.

Patient Selection

At Columbia University Medical Center, Dr. Bigliani performed 196 TSAs with a hybrid glenoid component (Bigliani-Flatow; Zimmer Biomet) in 169 patients between September 1998 and November 2007. All patients had received a diagnosis of primary glenohumeral arthritis as defined by Neer.¹⁸ Patients with previous surgery such as rotator cuff repair or subacromial decompression were included in our review, and patients with a nonprimary form of arthritis, such as rheumatoid, posttraumatic, or post-capsulorrhaphy arthritis, were excluded.

Operative Technique

For all surgeries, Dr. Bigliani performed a subscapularis tenotomy with regional anesthesia and a standard deltopectoral approach. A partial anterior capsulectomy was performed to increase the glenoid’s visibility. The inferior labrum was removed with a needle-tip bovie while the axillary nerve was being protected with a metal finger or narrow Darrach retractor. After reaming and trialing, the final glenoid component was cemented into place. Cement was placed only in the peg or keel holes and pressurized twice before final implantation. Of the 196 glenoid components, 168 (86%) were pegged and 28 (14%) keeled; in addition,190 of these components were all-polyethylene, whereas 6 had trabecular-metal backing. All glenoid components incorporated the hybrid design of dual radii of curvature. After the glenoid was cemented, the final humeral component was placed in 30° of retroversion. Whenever posterior wear was found, retroversion was reduced by 5° to 10°. The humeral prosthesis was cemented in cases (104/196, 53%) of poor bone quality or a large canal.

After surgery, the patient’s sling was fitted with an abduction pillow and a swathe, to be worn the first 24 hours, and the arm was passively ranged. Patients typically were discharged on postoperative day 2. Then, for 2 weeks, they followed an assisted passive range of motion (ROM) protocol, with limited external rotation, for promotion of subscapularis healing.

Clinical Outcomes

Dr. Bigliani assessed preoperative ROM in all planes. During initial evaluation, patients completed a questionnaire that consisted of the 36-Item Short Form Health Survey^19,20 (SF-36) and the American Shoulder and Elbow Surgeons²¹ (ASES) and Simple Shoulder Test²² (SST) surveys. Postoperative clinical data were collected from office follow-up visits, survey questionnaires, or both. Postoperative office data included ROM, subscapularis integrity testing (belly-press or lift-off), and any complications. Patients with <1 year of office follow-up were excluded. In addition, the same survey questionnaire that was used before surgery was mailed to all patients after surgery; then, for anyone who did not respond by mail, we attempted contact by telephone. Neer criteria were based on patients’ subjective assessment of each arm on a 3-point Likert scale (1 = very satisfied, 2 = satisfied, 3 = dissatisfied). Patients were also asked about any specific complications or revision operations since their index procedure.

Physical examination and office follow-up data were obtained for 129 patients (148/196 shoulders, 76% follow-up) at a mean of 3.7 years (range 1.0-10.2 years) after surgery. Surveys were completed by 117 patients (139/196 shoulders, 71% follow-up) at a mean of 5.1 years (range, 1.6-11.2 years) after surgery. Only 15 patients had neither 1 year of office follow-up nor a completed questionnaire. The remaining 154 patients (178/196 shoulders, 91% follow-up) had clinical follow-up with office, mail, or telephone questionnaire at a mean of 4.8 years (range, 1.0-11.2 years) after surgery. This cohort of patients was used to determine rates of surgical revisions, subscapularis tears, dislocations, and other complications.

Radiographic Outcomes

Patients were included in the radiographic analysis if they had a shoulder radiograph at least 1 year after surgery. One hundred nineteen patients (136/196 shoulders, 69% follow-up) had radiographic follow-up at a mean of 3.7 years (range, 1.0-9.4 years) after surgery.

Statistical Analysis

Statistical analysis was performed with Stata Version 10.0. Paired t tests were used to compare preoperative and postoperative numerical data, including ROM and survey scores. We calculated 95% confidence intervals (CIs) and set statistical significance at P < .05. For qualitative measures, the Fisher exact test was used. Survivorship analysis was performed according to the Kaplan-Meier method, with right-censored data for no event or missing data.²⁵

Results

Clinical Analysis of Demographics

In demographics, the clinical and radiographic patient subgroups were similar to each other and to the overall study population (Table 2). Of 196 patients overall, 16 (8%) had a concomitant rotator cuff repair, and 27 (14%) underwent staged bilateral shoulder arthroplasties.

Clinical Analysis of ROM and Survey Scores

Operative shoulder ROM in forward elevation, external rotation at side, external rotation in abduction, and internal rotation all showed statistically significant (P < .001) improvement from before surgery to after surgery. Over 3.7 years, mean (SD) forward elevation improved from 107.3° (34.8°) to 159.0° (29.4°), external rotation at side improved from 20.4° (16.7°) to 49.4° (11.3°), and external rotation in abduction improved from 53.7° (24.3°) to 84.7° (9.1°). Internal rotation improved from a mean (SD) vertebral level of S1 (6.0 levels) to T9 (3.7 levels).

All validated survey scores also showed statistically significant (P < .001) improvement from before surgery to after surgery. Over 5.1 years, mean (SD) SF-36 scores improved from 64.9 (13.4) to 73.6 (17.1), ASES scores improved from 41.1 (22.5) to 82.7 (17.7), SST scores improved from 3.9 (2.8) to 9.7 (2.2), and visual analog scale pain scores improved from 5.6 (3.2) to 1.4 (2.1). Of 139 patients with follow-up, 130 (93.5%) were either satisfied or very satisfied with their TSA, and only 119 (86%) were either satisfied or very satisfied with the nonoperative shoulder.

Clinical Analysis of Postoperative Complications

Of the 178 shoulders evaluated for complications, 3 (1.7%) underwent revision surgery. Mean time to revision was 2.3 years (range, 1.5-3.9 years). Two revisions involved the glenoid component, and the third involved the humerus. In one of the glenoid cases, a 77-year-old woman fell and sustained a fracture at the base of the trabecular metal glenoid pegs; her component was revised to an all-polyethylene component, and she had no further complications. In the other glenoid case, a 73-year-old man’s all-polyethylene component loosened after 2 years and was revised to a trabecular metal implant, which loosened as well and was later converted to a hemiarthroplasty. In the humeral case, a 33-year-old man had his 4-year-old index TSA revised to a cemented stem and had no further complications.

Table 4 compares the clinical and radiographic outcomes of patients who required subscapularis repair, capsular shift, or implant revision with the outcomes of all other study patients, and Figure 3 shows Kaplan-Meier survivorship.

Postoperative Radiographic Analysis

Glenoid Component. At a mean of 3.7 years (minimum, 1 year) after surgery, 86 (63%) of 136 radiographically evaluated shoulders showed no glenoid lucencies; the other 50 (37%) showed ≥1 lucency. Of the 136 shoulders, 33 (24%) had a Lazarus score of 1, 15 (11%) had a score of 2, and only 2 (2%) had a score of 3. None of the shoulders had a score of 4 or 5.

Humeral Component. Of the 136 shoulders, 91 (67%) showed no lucencies in any of the 8 humeral stem zones; the other 45 (33%) showed 1 to 3 lucencies. Thirty (22%) of the 136 shoulders had 1 stem lucency zone, 8 (6%) had 2, and 3 (2%) had 3. None of the shoulders had >3 periprosthetic zones with lucent lines.

Discussion

In this article, we describe a hybrid glenoid TSA component with dual radii of curvature. Its central portion is congruent with the humeral head, and its peripheral portion is noncongruent and larger. The most significant finding of our study is the low rate (1.1%) of glenoid component revision 4.8 years after surgery. This rate is the lowest that has been reported in a study of ≥100 patients. Overall implant survival appeared as an almost flat Kaplan-Meir curve. We attribute this low revision rate to improved biomechanics with the hybrid glenoid design. 

Symptomatic glenoid component loosening is the most common TSA complication.^1,26-28 In a review of 73 Neer TSAs, Cofield7 found glenoid radiolucencies in 71% of patients 3.8 years after surgery. Radiographic evidence of loosening, defined as component migration, or tilt, or a circumferential lucency 1.5 mm thick, was present in another 11% of patients, and 4.1% developed symptomatic loosening that required glenoid revision. In a study with 12.2-year follow-up, Torchia and colleagues³ found rates of 84% for glenoid radiolucencies, 44% for radiographic loosening, and 5.6% for symptomatic loosening that required revision. In a systematic review of studies with follow-up of ≥10 years, Bohsali and colleagues²⁷ found similar lucency and radiographic loosening rates and a 7% glenoid revision rate. These data suggest glenoid radiolucencies may progress to component loosening.

Degree of joint congruence is a key factor in glenoid loosening. Neer’s congruent design increases the contact area with concentric loading and reduces glenohumeral translation, which leads to reduced polyethylene wear and improved joint stability. In extreme arm positions, however, humeral head subluxation results in edge loading and a glenoid rocking-horse effect.^{9-13,17,29-31} Conversely, nonconforming implants allow increased glenohumeral translation without edge loading,¹⁴ though they also reduce the relative glenohumeral contact area and thus transmit more contact stress to the glenoid.^16,17 A hybrid glenoid component with central conforming and peripheral nonconforming zones may reduce the rocking-horse effect while maximizing ROM and joint stability. Wang and colleagues32 studied the biomechanical properties of this glenoid design and found that the addition of a central conforming region did not increase edge loading.

Additional results from our study support the efficacy of a hybrid glenoid component. Patients’ clinical outcomes improved significantly. At 5.1 years after surgery, 93.5% of patients were satisfied or very satisfied with their procedure and reported less satisfaction (86%) with the nonoperative shoulder. Also significant was the reduced number of radiolucencies. At 3.7 years after surgery, the overall percentage of shoulders with ≥1 glenoid radiolucency was 37%, considerably lower than the 82% reported by Cofield7 and the rates in more recent studies.^3,16,33-36 Of the 178 shoulders in our study, 10 (5.6%) had subscapularis tears, and 6 (3.4%) of 178 had these tears surgically repaired. This 3.4% compares favorably with the 5.9% (of 119 patients) found by Miller and colleagues37 28 months after surgery. Of our 178 shoulders, 27 (15.2%) had clinically significant postoperative complications; 18 (10.1%) of the 178 had these complications surgically treated, and 9 (5.1%) had them managed nonoperatively. Bohsali and colleagues²⁷ systematically reviewed 33 TSA studies and found a slightly higher complication rate (16.3%) 5.3 years after surgery. Furthermore, in our study, the 11 patients who underwent revision, capsular shift, or subscapularis repair had final outcomes comparable to those of the rest of our study population.

Our study had several potential weaknesses. First, its minimum clinical and radiographic follow-up was 1 year, whereas most long-term TSA series set a minimum of 2 years. We used 1 year because this was the first clinical study of the hybrid glenoid component design, and we wanted to maximize its sample size by reporting on intermediate-length outcomes. Even so, 93% (166/178) of our clinical patients and 83% (113/136) of our radiographic patients have had ≥2 years of follow-up, and we continue to follow all study patients for long-term outcomes. Another weakness of the study was its lack of a uniform group of patients with all the office, survey, complications, and radiographic data. Our retrospective study design made it difficult to obtain such a group without significantly reducing the sample size, so we divided patients into 4 data groups. A third potential weakness was the study’s variable method for collecting complications data. Rates of complications in the 178 shoulders were calculated from either office evaluation or patient self-report by mail or telephone. This data collection method is subject to recall bias, but mail and telephone contact was needed so the study would capture the large number of patients who had traveled to our institution for their surgery or had since moved away. Fourth, belly-press and lift-off tests were used in part to assess subscapularis function, but recent literature suggests post-TSA subscapularis assessment can be unreliable.³⁸ These tests may be positive in up to two-thirds of patients after 2 years.³⁹ Fifth, the generalizability of our findings to diagnoses such as rheumatoid and posttraumatic arthritis is limited. We had to restrict the study to patients with primary glenohumeral arthritis in order to minimize confounders.

This study’s main strength is its description of the clinical and radiographic outcomes of using a single prosthetic system in operations performed by a single surgeon in a large number of patients. This was the first and largest study evaluating the clinical and radiographic outcomes of this hybrid glenoid implant. Excluding patients with nonprimary arthritis allowed us to minimize potential confounding factors that affect patient outcomes. In conclusion, our study results showed the favorable clinical and radiographic outcomes of TSAs that have a hybrid glenoid component with dual radii of curvature. At a mean of 3.7 years after surgery, 63% of patients had no glenoid lucencies, and, at a mean of 4.8 years, only 1.7% of patients required revision. We continue to follow these patients to obtain long-term results of this innovative prosthesis.

From 2013 to 2016, all U.S. immunization information systems showed progress in bidirectional information exchange with EHRs, said Neil Murthy, MD, and his associates at the National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta.

Across all 55 jurisdictions in 49 states and six cities in the United States using immunization information systems (IIS), 106% of U.S. births were registered in IIS in 2016, which is an increase from 102% in 2013; percentages may exceed 100%, because a child who is born in one state but who lives in a different state might be recorded in both IISs.

FotoMaximum/Thinkstock

From 2013 to 2016, all U.S. immunization information systems showed progress in bidirectional information exchange with EHRs, said Neil Murthy, MD, and his associates at the National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta.

Across all 55 jurisdictions in 49 states and six cities in the United States using immunization information systems (IIS), 106% of U.S. births were registered in IIS in 2016, which is an increase from 102% in 2013; percentages may exceed 100%, because a child who is born in one state but who lives in a different state might be recorded in both IISs.

FotoMaximum/Thinkstock

From 2013 to 2016, all U.S. immunization information systems showed progress in bidirectional information exchange with EHRs, said Neil Murthy, MD, and his associates at the National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta.

Across all 55 jurisdictions in 49 states and six cities in the United States using immunization information systems (IIS), 106% of U.S. births were registered in IIS in 2016, which is an increase from 102% in 2013; percentages may exceed 100%, because a child who is born in one state but who lives in a different state might be recorded in both IISs.

FotoMaximum/Thinkstock

A 7-day limit on the initial opioid prescription may be sufficient for many common general surgery procedures, including hernia surgery and gynecologic procedures, findings of a large retrospective study suggest.

Rebecca E. Scully, MD, of the Center for Surgery and Public Health at Brigham and Women’s Hospital in Boston, and her associates examined opioid pain medication prescriptions and refills from records of the Military Health System Data Repository and the TRICARE insurance program of 215,140 opioid-naive patients. These patients were aged 18-64 years who underwent either cholecystectomy, appendectomy, inguinal hernia repair, anterior cruciate ligament reconstruction, rotator cuff tear repair, discectomy, mastectomy, or hysterectomy (JAMA Surg. 2017. doi: 10.1001/jamasurg.2017.3132). Only 20% of the covered individuals are active members of the U.S. military. The mean age was 40 years; 50% were male, and 60% were white.

For appendectomy, cholecystectomy, and hysterectomy, the prescription was a median 4 days. For inguinal hernia repair, anterior cruciate ligament repair, rotator cuff repair, and mastectomy, the initial prescription was for 5 days. For discectomy, the median was 7 days.

Refill rates were the least at 11.3% for cholecystectomy and the most at 39.3% after anterior cruciate ligament repair. The time after the initial prescription until a refill was a median 6 days for appendectomy, cholecystectomy, and inguinal hernia repair, compared with a median 10 days for discectomy. The median duration of a refill prescription was 4 days for appendectomy, cholecystectomy, hernia repair, and hysterectomy versus 8 days for discectomy.

“Although 7 days appears to be more than adequate for many patients undergoing common general surgery and gynecologic procedures, prescription lengths likely should be extended to 10 days, particularly after common neurosurgical and musculoskeletal procedures, recognizing that as many as 40% of patients may still require one refill at a 7-day limit,” Dr. Scully and her associates said.

Although this study did not include rates of unused prescriptions or use of nonopioid pain relievers such as acetaminophen or NSAIDs, it did include a large population considered to be nationally representative “in many respects,” and it included a variety of procedures for which patients are commonly discharged to home, the researchers said.

The study was funded in part by the Department of Defense/Henry M. Jackson Foundation. The investigators had no conflict of interests. Adil H. Haider, MD, MPH, is deputy editor of JAMA Surgery, but he was not involved in any of the decisions regarding review of the manuscript or its acceptance.

A 7-day limit on the initial opioid prescription may be sufficient for many common general surgery procedures, including hernia surgery and gynecologic procedures, findings of a large retrospective study suggest.

Rebecca E. Scully, MD, of the Center for Surgery and Public Health at Brigham and Women’s Hospital in Boston, and her associates examined opioid pain medication prescriptions and refills from records of the Military Health System Data Repository and the TRICARE insurance program of 215,140 opioid-naive patients. These patients were aged 18-64 years who underwent either cholecystectomy, appendectomy, inguinal hernia repair, anterior cruciate ligament reconstruction, rotator cuff tear repair, discectomy, mastectomy, or hysterectomy (JAMA Surg. 2017. doi: 10.1001/jamasurg.2017.3132). Only 20% of the covered individuals are active members of the U.S. military. The mean age was 40 years; 50% were male, and 60% were white.

For appendectomy, cholecystectomy, and hysterectomy, the prescription was a median 4 days. For inguinal hernia repair, anterior cruciate ligament repair, rotator cuff repair, and mastectomy, the initial prescription was for 5 days. For discectomy, the median was 7 days.

Refill rates were the least at 11.3% for cholecystectomy and the most at 39.3% after anterior cruciate ligament repair. The time after the initial prescription until a refill was a median 6 days for appendectomy, cholecystectomy, and inguinal hernia repair, compared with a median 10 days for discectomy. The median duration of a refill prescription was 4 days for appendectomy, cholecystectomy, hernia repair, and hysterectomy versus 8 days for discectomy.

“Although 7 days appears to be more than adequate for many patients undergoing common general surgery and gynecologic procedures, prescription lengths likely should be extended to 10 days, particularly after common neurosurgical and musculoskeletal procedures, recognizing that as many as 40% of patients may still require one refill at a 7-day limit,” Dr. Scully and her associates said.

Although this study did not include rates of unused prescriptions or use of nonopioid pain relievers such as acetaminophen or NSAIDs, it did include a large population considered to be nationally representative “in many respects,” and it included a variety of procedures for which patients are commonly discharged to home, the researchers said.

The study was funded in part by the Department of Defense/Henry M. Jackson Foundation. The investigators had no conflict of interests. Adil H. Haider, MD, MPH, is deputy editor of JAMA Surgery, but he was not involved in any of the decisions regarding review of the manuscript or its acceptance.

A 7-day limit on the initial opioid prescription may be sufficient for many common general surgery procedures, including hernia surgery and gynecologic procedures, findings of a large retrospective study suggest.

Rebecca E. Scully, MD, of the Center for Surgery and Public Health at Brigham and Women’s Hospital in Boston, and her associates examined opioid pain medication prescriptions and refills from records of the Military Health System Data Repository and the TRICARE insurance program of 215,140 opioid-naive patients. These patients were aged 18-64 years who underwent either cholecystectomy, appendectomy, inguinal hernia repair, anterior cruciate ligament reconstruction, rotator cuff tear repair, discectomy, mastectomy, or hysterectomy (JAMA Surg. 2017. doi: 10.1001/jamasurg.2017.3132). Only 20% of the covered individuals are active members of the U.S. military. The mean age was 40 years; 50% were male, and 60% were white.

For appendectomy, cholecystectomy, and hysterectomy, the prescription was a median 4 days. For inguinal hernia repair, anterior cruciate ligament repair, rotator cuff repair, and mastectomy, the initial prescription was for 5 days. For discectomy, the median was 7 days.

Refill rates were the least at 11.3% for cholecystectomy and the most at 39.3% after anterior cruciate ligament repair. The time after the initial prescription until a refill was a median 6 days for appendectomy, cholecystectomy, and inguinal hernia repair, compared with a median 10 days for discectomy. The median duration of a refill prescription was 4 days for appendectomy, cholecystectomy, hernia repair, and hysterectomy versus 8 days for discectomy.

“Although 7 days appears to be more than adequate for many patients undergoing common general surgery and gynecologic procedures, prescription lengths likely should be extended to 10 days, particularly after common neurosurgical and musculoskeletal procedures, recognizing that as many as 40% of patients may still require one refill at a 7-day limit,” Dr. Scully and her associates said.

Although this study did not include rates of unused prescriptions or use of nonopioid pain relievers such as acetaminophen or NSAIDs, it did include a large population considered to be nationally representative “in many respects,” and it included a variety of procedures for which patients are commonly discharged to home, the researchers said.

The study was funded in part by the Department of Defense/Henry M. Jackson Foundation. The investigators had no conflict of interests. Adil H. Haider, MD, MPH, is deputy editor of JAMA Surgery, but he was not involved in any of the decisions regarding review of the manuscript or its acceptance.

WASHINGTON – Research into alcoholic liver disease, drug-induced liver injury, the complications of chronic liver disease, and cholestatic liver diseases were among the clinical hepatology highlights presented at the annual meeting of the American Association for the Study of Liver Diseases.

This year’s debrief was given by Kris V. Kowdley, MD, of Swedish Medical Center in Seattle.

dfulton@frontlinemedcom.com

On Twitter @denisefulton

WASHINGTON – Research into alcoholic liver disease, drug-induced liver injury, the complications of chronic liver disease, and cholestatic liver diseases were among the clinical hepatology highlights presented at the annual meeting of the American Association for the Study of Liver Diseases.

This year’s debrief was given by Kris V. Kowdley, MD, of Swedish Medical Center in Seattle.

dfulton@frontlinemedcom.com

On Twitter @denisefulton

WASHINGTON – Research into alcoholic liver disease, drug-induced liver injury, the complications of chronic liver disease, and cholestatic liver diseases were among the clinical hepatology highlights presented at the annual meeting of the American Association for the Study of Liver Diseases.

This year’s debrief was given by Kris V. Kowdley, MD, of Swedish Medical Center in Seattle.

dfulton@frontlinemedcom.com

On Twitter @denisefulton

SAN DIEGO – A variety of legislation that’s currently under consideration in Washington has great potential to affect the field of rheumatology and its patients, but ongoing efforts to advocate for the specialty and patients are showing signs of paying off in some areas, Angus Worthing, MD, said at the annual meeting of the American College of Rheumatology.

Affordable Care Act (ACA)

Alicia Ault/Frontline Medical News

• Provide sufficient, affordable, continuous coverage that encourages access to high-quality care for all.
• Prohibit exclusions based on preexisting conditions.
• Allow children to remain on parent’s insurance until age 26 years.
• Remove excessive administrative burdens that take focus away from patient care.
• Cap annual out-of-pocket costs and ban lifetime limits.
• Have affordable premiums, deductibles, and cost sharing.
• Continue the 10 essential health benefits that are required for ACA marketplace plans.

Alliance for Transparent & Affordable Prescriptions (ATAP)

The ACR convened this alliance along with the Coalition of State Rheumatology Organizations, the Global Healthy Living Foundation, the Association of Women in Rheumatology, the Rheumatology Nurses Society, and others to try to bring transparency to how pharmacy benefit managers (PBMs) operate in getting certain drugs on the formularies of payers. The ATAP recently had some success in making lawmakers aware of the PBM’s role in influencing drug prices via rebates to drug manufacturers. At a Congressional hearing in Oct. 2017, after many visits from rheumatologists and members of ATAP, the members of the Senate Committee on Health, Education, Labor, and Pensions “held the feet of these PBMs to the fire a little bit asking them about these rebates,” Dr. Worthing said, where at one point committee chair Sen. Lamar Alexander (R-Tenn.) asked, “ ‘Do we really need these rebates?’ ”

National Institutes of Health budget

After the National Institutes of Health received a $2 billion increase in funding for fiscal year 2017, the Trump administration proposed last summer to cut the NIH budget by 22%. Since then, however, bills to increase the NIH budget by $1.1 billion from the House and by $2 billion from the Senate have made their way through committees. But a budget must be passed by Congress and then signed by the president to make a potential budget increase a reality. Otherwise, a continuing resolution would leave the current level of funding in place through fiscal year 2018, Dr. Worthing noted.

Patients’ Access to Treatments Act of 2017 (H.R. 2999)

This bill has been raised for a fourth time after not making it past committees in previous Congresses, but the prospects for it passing appear somewhat better this time around, Dr. Worthing said. It would prevent insurance companies from putting drugs in specialty tiers that require patients to pay increasingly higher rates of coinsurance for the drugs on different tiers.

“It has been gathering momentum. We hope to get it across the finish line. And if we don’t get this across, then we’ll join with the coalition that rheumatology has formed around this issue of access to specialty treatments some other way, because this is a burning issue for us and our patients,” he said.
 

Medicare Access to Rehabilitation Services Act of 2017 (H.R. 807 and S. 253)

This bill would repeal the annual cap that was placed on rehabilitation services for patients covered by Medicare in 1997. The bill has bipartisan, majority support and has been gaining momentum for the past 4 years, Dr. Worthing said. It was advanced from both Senate and House committees in Oct. 2017.

jevans@frontlinemedcom.com

SAN DIEGO – A variety of legislation that’s currently under consideration in Washington has great potential to affect the field of rheumatology and its patients, but ongoing efforts to advocate for the specialty and patients are showing signs of paying off in some areas, Angus Worthing, MD, said at the annual meeting of the American College of Rheumatology.

Affordable Care Act (ACA)

Alicia Ault/Frontline Medical News

• Provide sufficient, affordable, continuous coverage that encourages access to high-quality care for all.
• Prohibit exclusions based on preexisting conditions.
• Allow children to remain on parent’s insurance until age 26 years.
• Remove excessive administrative burdens that take focus away from patient care.
• Cap annual out-of-pocket costs and ban lifetime limits.
• Have affordable premiums, deductibles, and cost sharing.
• Continue the 10 essential health benefits that are required for ACA marketplace plans.

Alliance for Transparent & Affordable Prescriptions (ATAP)

The ACR convened this alliance along with the Coalition of State Rheumatology Organizations, the Global Healthy Living Foundation, the Association of Women in Rheumatology, the Rheumatology Nurses Society, and others to try to bring transparency to how pharmacy benefit managers (PBMs) operate in getting certain drugs on the formularies of payers. The ATAP recently had some success in making lawmakers aware of the PBM’s role in influencing drug prices via rebates to drug manufacturers. At a Congressional hearing in Oct. 2017, after many visits from rheumatologists and members of ATAP, the members of the Senate Committee on Health, Education, Labor, and Pensions “held the feet of these PBMs to the fire a little bit asking them about these rebates,” Dr. Worthing said, where at one point committee chair Sen. Lamar Alexander (R-Tenn.) asked, “ ‘Do we really need these rebates?’ ”

National Institutes of Health budget

After the National Institutes of Health received a $2 billion increase in funding for fiscal year 2017, the Trump administration proposed last summer to cut the NIH budget by 22%. Since then, however, bills to increase the NIH budget by $1.1 billion from the House and by $2 billion from the Senate have made their way through committees. But a budget must be passed by Congress and then signed by the president to make a potential budget increase a reality. Otherwise, a continuing resolution would leave the current level of funding in place through fiscal year 2018, Dr. Worthing noted.

Patients’ Access to Treatments Act of 2017 (H.R. 2999)

This bill has been raised for a fourth time after not making it past committees in previous Congresses, but the prospects for it passing appear somewhat better this time around, Dr. Worthing said. It would prevent insurance companies from putting drugs in specialty tiers that require patients to pay increasingly higher rates of coinsurance for the drugs on different tiers.

“It has been gathering momentum. We hope to get it across the finish line. And if we don’t get this across, then we’ll join with the coalition that rheumatology has formed around this issue of access to specialty treatments some other way, because this is a burning issue for us and our patients,” he said.
 

Medicare Access to Rehabilitation Services Act of 2017 (H.R. 807 and S. 253)

This bill would repeal the annual cap that was placed on rehabilitation services for patients covered by Medicare in 1997. The bill has bipartisan, majority support and has been gaining momentum for the past 4 years, Dr. Worthing said. It was advanced from both Senate and House committees in Oct. 2017.

jevans@frontlinemedcom.com

SAN DIEGO – A variety of legislation that’s currently under consideration in Washington has great potential to affect the field of rheumatology and its patients, but ongoing efforts to advocate for the specialty and patients are showing signs of paying off in some areas, Angus Worthing, MD, said at the annual meeting of the American College of Rheumatology.

Affordable Care Act (ACA)

Alicia Ault/Frontline Medical News

• Provide sufficient, affordable, continuous coverage that encourages access to high-quality care for all.
• Prohibit exclusions based on preexisting conditions.
• Allow children to remain on parent’s insurance until age 26 years.
• Remove excessive administrative burdens that take focus away from patient care.
• Cap annual out-of-pocket costs and ban lifetime limits.
• Have affordable premiums, deductibles, and cost sharing.
• Continue the 10 essential health benefits that are required for ACA marketplace plans.

Alliance for Transparent & Affordable Prescriptions (ATAP)

The ACR convened this alliance along with the Coalition of State Rheumatology Organizations, the Global Healthy Living Foundation, the Association of Women in Rheumatology, the Rheumatology Nurses Society, and others to try to bring transparency to how pharmacy benefit managers (PBMs) operate in getting certain drugs on the formularies of payers. The ATAP recently had some success in making lawmakers aware of the PBM’s role in influencing drug prices via rebates to drug manufacturers. At a Congressional hearing in Oct. 2017, after many visits from rheumatologists and members of ATAP, the members of the Senate Committee on Health, Education, Labor, and Pensions “held the feet of these PBMs to the fire a little bit asking them about these rebates,” Dr. Worthing said, where at one point committee chair Sen. Lamar Alexander (R-Tenn.) asked, “ ‘Do we really need these rebates?’ ”

National Institutes of Health budget

After the National Institutes of Health received a $2 billion increase in funding for fiscal year 2017, the Trump administration proposed last summer to cut the NIH budget by 22%. Since then, however, bills to increase the NIH budget by $1.1 billion from the House and by $2 billion from the Senate have made their way through committees. But a budget must be passed by Congress and then signed by the president to make a potential budget increase a reality. Otherwise, a continuing resolution would leave the current level of funding in place through fiscal year 2018, Dr. Worthing noted.

Patients’ Access to Treatments Act of 2017 (H.R. 2999)

This bill has been raised for a fourth time after not making it past committees in previous Congresses, but the prospects for it passing appear somewhat better this time around, Dr. Worthing said. It would prevent insurance companies from putting drugs in specialty tiers that require patients to pay increasingly higher rates of coinsurance for the drugs on different tiers.

“It has been gathering momentum. We hope to get it across the finish line. And if we don’t get this across, then we’ll join with the coalition that rheumatology has formed around this issue of access to specialty treatments some other way, because this is a burning issue for us and our patients,” he said.
 

Medicare Access to Rehabilitation Services Act of 2017 (H.R. 807 and S. 253)

This bill would repeal the annual cap that was placed on rehabilitation services for patients covered by Medicare in 1997. The bill has bipartisan, majority support and has been gaining momentum for the past 4 years, Dr. Worthing said. It was advanced from both Senate and House committees in Oct. 2017.

jevans@frontlinemedcom.com

SAN DIEGO – In what may be the largest study of its kind, British researchers have linked obesity to significantly higher odds of rheumatoid arthritis disease activity and disability.

“This study emphasizes that obesity can have a profound effect on treatment goals in rheumatoid arthritis,” says Elena Nikiphorou, MD, of King’s College London, who presented the study findings at the annual meeting of the American College of Rheumatology. “Obesity reduced the odds of achieving remission or low disease activity by around 30%. And the odds of having disability were increased by 63%. This confirms what’s been shown in other, smaller studies.”

“In my view the mechanical risk to the joint outweighs any possible ‘protective’ effect of RA,” Dr. Matteson added in an interview.

For the new study, Dr. Nikiphorou and colleagues compiled statistics from two consecutive United Kingdom RA inception cohorts. One tracked 1,465 patients for up to 25 years (median follow-up, 10 years), and the other tracked 1,236 patients for as many as 10 years (median follow-up, 6 years).

At baseline, 37.2% of 2,420 patients (90% of total) were overweight, and 21.3% were obese. Average body mass index (BMI) rose between the two consecutive studies from 25.5 to 27.6.

The researchers found that obesity was linked to lower likelihoods of remission and low disease activity status (odds ratio, 0.71; 95% confidence interval, 0.55-0.93 and OR, 0.69; 95% CI, 0.55-0.87, respectively.) After controlling for factors such as age and gender, they also saw slightly lower odds of remission in those with higher BMI (OR, 0.97; 95% CI, 0.95-0.99). But there was no statistically significant link between higher BMI and low disease activity status.

The study also connected obesity to higher odds of disability (OR, 1.63; 95% CI, 1.20-2.23). Furthermore, higher BMI was linked to higher odds of disability (OR, 1.04; 95% CI, 1.01-1.06).

Study lead author Dr. Nikiphorou, who spoke in an interview and in comments at an ACR press conference, said “this study emphasizes that obesity can have a profound effect on treatment goals in rheumatoid arthritis. It creates a strong case for addressing BMI and addressing obesity, flagging it up to primary care.”

She added that rheumatologists too often focus on only rheumatoid conditions. “We place so much evidence on disease activity scores,” she said. “How often do we really address the patient in terms of other things going on, including obesity? What we can do is include discussion of BMI, exercise, nutrition.”

Dr. Nikiphorou and Dr. Matteson report no relevant disclosures. No specific study funding is reported.

This article was updated 11/10/17.

SAN DIEGO – In what may be the largest study of its kind, British researchers have linked obesity to significantly higher odds of rheumatoid arthritis disease activity and disability.

“This study emphasizes that obesity can have a profound effect on treatment goals in rheumatoid arthritis,” says Elena Nikiphorou, MD, of King’s College London, who presented the study findings at the annual meeting of the American College of Rheumatology. “Obesity reduced the odds of achieving remission or low disease activity by around 30%. And the odds of having disability were increased by 63%. This confirms what’s been shown in other, smaller studies.”

“In my view the mechanical risk to the joint outweighs any possible ‘protective’ effect of RA,” Dr. Matteson added in an interview.

For the new study, Dr. Nikiphorou and colleagues compiled statistics from two consecutive United Kingdom RA inception cohorts. One tracked 1,465 patients for up to 25 years (median follow-up, 10 years), and the other tracked 1,236 patients for as many as 10 years (median follow-up, 6 years).

At baseline, 37.2% of 2,420 patients (90% of total) were overweight, and 21.3% were obese. Average body mass index (BMI) rose between the two consecutive studies from 25.5 to 27.6.

The researchers found that obesity was linked to lower likelihoods of remission and low disease activity status (odds ratio, 0.71; 95% confidence interval, 0.55-0.93 and OR, 0.69; 95% CI, 0.55-0.87, respectively.) After controlling for factors such as age and gender, they also saw slightly lower odds of remission in those with higher BMI (OR, 0.97; 95% CI, 0.95-0.99). But there was no statistically significant link between higher BMI and low disease activity status.

The study also connected obesity to higher odds of disability (OR, 1.63; 95% CI, 1.20-2.23). Furthermore, higher BMI was linked to higher odds of disability (OR, 1.04; 95% CI, 1.01-1.06).

Study lead author Dr. Nikiphorou, who spoke in an interview and in comments at an ACR press conference, said “this study emphasizes that obesity can have a profound effect on treatment goals in rheumatoid arthritis. It creates a strong case for addressing BMI and addressing obesity, flagging it up to primary care.”

She added that rheumatologists too often focus on only rheumatoid conditions. “We place so much evidence on disease activity scores,” she said. “How often do we really address the patient in terms of other things going on, including obesity? What we can do is include discussion of BMI, exercise, nutrition.”

Dr. Nikiphorou and Dr. Matteson report no relevant disclosures. No specific study funding is reported.

This article was updated 11/10/17.

SAN DIEGO – In what may be the largest study of its kind, British researchers have linked obesity to significantly higher odds of rheumatoid arthritis disease activity and disability.

“This study emphasizes that obesity can have a profound effect on treatment goals in rheumatoid arthritis,” says Elena Nikiphorou, MD, of King’s College London, who presented the study findings at the annual meeting of the American College of Rheumatology. “Obesity reduced the odds of achieving remission or low disease activity by around 30%. And the odds of having disability were increased by 63%. This confirms what’s been shown in other, smaller studies.”

“In my view the mechanical risk to the joint outweighs any possible ‘protective’ effect of RA,” Dr. Matteson added in an interview.

For the new study, Dr. Nikiphorou and colleagues compiled statistics from two consecutive United Kingdom RA inception cohorts. One tracked 1,465 patients for up to 25 years (median follow-up, 10 years), and the other tracked 1,236 patients for as many as 10 years (median follow-up, 6 years).

At baseline, 37.2% of 2,420 patients (90% of total) were overweight, and 21.3% were obese. Average body mass index (BMI) rose between the two consecutive studies from 25.5 to 27.6.

The researchers found that obesity was linked to lower likelihoods of remission and low disease activity status (odds ratio, 0.71; 95% confidence interval, 0.55-0.93 and OR, 0.69; 95% CI, 0.55-0.87, respectively.) After controlling for factors such as age and gender, they also saw slightly lower odds of remission in those with higher BMI (OR, 0.97; 95% CI, 0.95-0.99). But there was no statistically significant link between higher BMI and low disease activity status.

The study also connected obesity to higher odds of disability (OR, 1.63; 95% CI, 1.20-2.23). Furthermore, higher BMI was linked to higher odds of disability (OR, 1.04; 95% CI, 1.01-1.06).

Study lead author Dr. Nikiphorou, who spoke in an interview and in comments at an ACR press conference, said “this study emphasizes that obesity can have a profound effect on treatment goals in rheumatoid arthritis. It creates a strong case for addressing BMI and addressing obesity, flagging it up to primary care.”

She added that rheumatologists too often focus on only rheumatoid conditions. “We place so much evidence on disease activity scores,” she said. “How often do we really address the patient in terms of other things going on, including obesity? What we can do is include discussion of BMI, exercise, nutrition.”

Dr. Nikiphorou and Dr. Matteson report no relevant disclosures. No specific study funding is reported.

This article was updated 11/10/17.

WASHINGTON – During and after liver transplant, the reaction of the intestinal microbiota may be a critical determinant of outcomes; preliminary data from a cohort study may provide some clarification of what modulates gut microbiota post transplantation and shed light on predictive factors.

Anna-Catrin Uhlemann, MD, PhD, of Columbia University Medical Center, New York, noted that several studies in recent years sought to clarify influences on gut microbiota in people receiving liver transplants, but “there are still a number of important gaps in knowledge, including what exactly is the longitudinal evolution of the host transplant microbiome and what is the predictive value of pre- and early posttransplant dysbiosis on outcomes and complications.”

WASHINGTON – During and after liver transplant, the reaction of the intestinal microbiota may be a critical determinant of outcomes; preliminary data from a cohort study may provide some clarification of what modulates gut microbiota post transplantation and shed light on predictive factors.

Anna-Catrin Uhlemann, MD, PhD, of Columbia University Medical Center, New York, noted that several studies in recent years sought to clarify influences on gut microbiota in people receiving liver transplants, but “there are still a number of important gaps in knowledge, including what exactly is the longitudinal evolution of the host transplant microbiome and what is the predictive value of pre- and early posttransplant dysbiosis on outcomes and complications.”

WASHINGTON – During and after liver transplant, the reaction of the intestinal microbiota may be a critical determinant of outcomes; preliminary data from a cohort study may provide some clarification of what modulates gut microbiota post transplantation and shed light on predictive factors.

Anna-Catrin Uhlemann, MD, PhD, of Columbia University Medical Center, New York, noted that several studies in recent years sought to clarify influences on gut microbiota in people receiving liver transplants, but “there are still a number of important gaps in knowledge, including what exactly is the longitudinal evolution of the host transplant microbiome and what is the predictive value of pre- and early posttransplant dysbiosis on outcomes and complications.”

SAN DIEGO– Long before the horrific night of Oct. 1, the three trauma centers in the Las Vegas region were ready for a mass casualty event. It was understood among hospital leaders that the city could be the scene of a disaster that would demand a coordinated response from the city’s health care centers.

Then came the deadliest mass shooting in modern American history, and the extensive preparation turned out to have been well worth the time and effort, according to four trauma surgeons who spoke about the medical response to the massacre during a session at the annual clinical congress of the American College of Surgeons.

Courtesy of MountainView

Courtesy of UMC

Dr. Fildes said that the UMC staff were physically and emotionally exhausted by the ordeal, but proud of what they were able to do for these patients, and that pride carried them through the experience. “We had support from all over the country; people sent banners with hundreds of signatures. Something like 1,100 pizzas were sent to the UMC staff, and dozens and dozens of surgeons from all over the country offered to come help us.”
Dr. Fildes noted that he is not easily surprised given his daily work, but he was impressed by the generosity and courage of the patients in this crisis situation.
He concluded that, “This was all made possible because of planning, training, commitment by staff and ultimately, the bravery of the patients.”


Dr. Dort, Dr. Fildes, Dr. Kuhls, and Dr. Johnson had no relevant financial disclosures.

SAN DIEGO– Long before the horrific night of Oct. 1, the three trauma centers in the Las Vegas region were ready for a mass casualty event. It was understood among hospital leaders that the city could be the scene of a disaster that would demand a coordinated response from the city’s health care centers.

Then came the deadliest mass shooting in modern American history, and the extensive preparation turned out to have been well worth the time and effort, according to four trauma surgeons who spoke about the medical response to the massacre during a session at the annual clinical congress of the American College of Surgeons.

Courtesy of MountainView

Courtesy of UMC

Dr. Fildes said that the UMC staff were physically and emotionally exhausted by the ordeal, but proud of what they were able to do for these patients, and that pride carried them through the experience. “We had support from all over the country; people sent banners with hundreds of signatures. Something like 1,100 pizzas were sent to the UMC staff, and dozens and dozens of surgeons from all over the country offered to come help us.”
Dr. Fildes noted that he is not easily surprised given his daily work, but he was impressed by the generosity and courage of the patients in this crisis situation.
He concluded that, “This was all made possible because of planning, training, commitment by staff and ultimately, the bravery of the patients.”


Dr. Dort, Dr. Fildes, Dr. Kuhls, and Dr. Johnson had no relevant financial disclosures.

SAN DIEGO– Long before the horrific night of Oct. 1, the three trauma centers in the Las Vegas region were ready for a mass casualty event. It was understood among hospital leaders that the city could be the scene of a disaster that would demand a coordinated response from the city’s health care centers.

Then came the deadliest mass shooting in modern American history, and the extensive preparation turned out to have been well worth the time and effort, according to four trauma surgeons who spoke about the medical response to the massacre during a session at the annual clinical congress of the American College of Surgeons.

Courtesy of MountainView

Courtesy of UMC

Dr. Fildes said that the UMC staff were physically and emotionally exhausted by the ordeal, but proud of what they were able to do for these patients, and that pride carried them through the experience. “We had support from all over the country; people sent banners with hundreds of signatures. Something like 1,100 pizzas were sent to the UMC staff, and dozens and dozens of surgeons from all over the country offered to come help us.”
Dr. Fildes noted that he is not easily surprised given his daily work, but he was impressed by the generosity and courage of the patients in this crisis situation.
He concluded that, “This was all made possible because of planning, training, commitment by staff and ultimately, the bravery of the patients.”


Dr. Dort, Dr. Fildes, Dr. Kuhls, and Dr. Johnson had no relevant financial disclosures.

Central line–associated bloodstream infection (CLABSI) and catheter-associated urinary tract infection (CAUTI) are morbid and expensive healthcare-associated infections (HAIs).^1-8 While these HAIs are prevalent in intensive care units (ICUs) and general wards, most of the research, prevention efforts, and financial penalties have been focused in the ICU.^9,10 For hospitalists, who are taking a larger role in caring for the critically ill,^11,12 it is optimal to understand best preventive practices.

There has been a national puTash to standardize procedures and products to prevent CLABSI and CAUTI.^2,13-16 CLABSI has transitioned from a common ICU complication to a “never event.” Success has been reflected in the prevention of 25,000 CLABSIs over the last decade, translating to a 58% reduction in infections, with 6000 deaths prevented and $414 million saved.² CLABSI prevention principles have been applied to CAUTI prevention (ie, aseptic insertion, maintenance care, prompting removal) but with slower adoption¹⁷ and fewer dramatic CAUTI reductions,¹⁸ due in part to weaker recognition¹⁹ of CAUTI as a serious clinical event, despite its morbidity²⁰ and cost.²¹

Despite recent improvements in preventing HAIs, there is a marked variability in how hospitals perform in preventing these infections.²² To inform infection prevention strategies for a large-scale implementation project funded by the Agency for Healthcare Research and Quality and focused on ICUs with persistently elevated CLABSI and/or CAUTI rates,²³ we performed a systematic search of interventions to prevent CLABSI and CAUTI in the ICU setting. This evidence was synthesized to help units select and prioritize interventions to prevent these HAIs.

Literature Search Strategy

We performed a systematic search to identify CLABSI and CAUTI prevention studies and synthesized findings using a narrative review process. Using criteria developed and refined from seminal articles on the topic,^10,14,24-34 we searched the PubMed and Cochrane databases from their inception to October of 2015 using Medical Subject Headings (MeSHs) for “central venous catheters,” “CLABSI,” “central line associated bloodstream infection,” “catheter related bloodstream infection,” “intravascular devices,” “urinary catheterization,” “urinary catheters,” “urinary tract infections,” “CAUTI,” and “catheter associated urinary tract infections” and filtered for articles containing the MeSHs “intensive care unit” and “ICU.” Supplemental Figure 1 details the search, yielding 102 studies for CLABSI and 28 studies for CAUTI, including 7 studies with CLABSI and CAUTI interventions.

Eligibility Criteria Review

Study Design

We included randomized and nonrandomized studies that implemented at least 1 intervention to prevent CLABSI or CAUTI in an adult ICU setting and reported the preintervention or control group data to compare with the postintervention data. We excluded general ward, outpatient/ambulatory, and neonatal/pediatric settings. Interventions to prevent CLABSI or CAUTI were included. We excluded interventions focused on diagnosis or treatment or those that lacked adequate description of the intervention for replication. Studies with interventions that are no longer standard of care in the United States (US) were excluded, as were studies not available in English.

Outcomes

Primary Outcomes for Central Vascular Catheter Infection

• CLABSI: A lab-confirmed bloodstream infection in a patient who has had a central line for at least 48 hours on the date of the development of the bloodstream infection and without another known source of infection. We included studies that reported CLABSIs per 1000 central line days or those that provided data to permit calculation of this ratio. This measure is similar to current National Healthcare Safety Network (NHSN) surveillance definitions.²²
• Catheter-related bloodstream infection (CRBSI): A lab-confirmed bloodstream infection attributed to an intravascular catheter by a quantitative culture of the catheter tip or by differences in growth between catheter and peripheral venipuncture blood culture specimens.³⁵ This microbiologic definition of a central line bloodstream infection was often used prior to NHSN reporting, with rates provided as the number of CRBSIs per 1000 central line days.

Primary Outcome for Urinary Catheter Infection

• CAUTI: Urinary tract infection occurring in patients during or after the recent use of an indwelling urinary catheter. We included studies that reported CAUTIs per 1000 urinary catheter days or those that provided data to permit calculation of this ratio (similar to the current NHSN surveillance definitions).²² We excluded studies where CAUTI was defined as bacteriuria alone, without symptoms.

Secondary Outcomes

• Central line utilization ratio: The device utilization ratio (DUR) measure of central line use is calculated as central line days divided by patient days.
• Urinary catheter utilization ratio: The DUR measure of urinary catheter use is calculated as indwelling urinary catheter days divided by patient days, as used in NHSN surveillance, excluding other catheter types.²² We excluded other measures of urinary catheter use because of a large variation in definitions, which limits the ability to compare measures across studies.

Data Synthesis and Analysis

Information on the ICU and intervention type, intervention components, outcomes, and whether interventions were in use prior to the study was abstracted by CAUTI and CLABSI experts (JM and PKP) and confirmed by a second author.

We compared interventions found in the literature to components of the previously published urinary catheter “life cycle,” a conceptual model used to organize and prioritize interventions for a reduction in CAUTI (Figure 1).³⁶

Conceptual Model for Disrupting the Life Cycle of a Catheter

Our data analysis demonstrated that components of the urinary catheter life cycle (Figure 1) were useful and could be applied to vascular catheters, but changes were needed to make the model more valuable to hospitalists implementing CLABSI and CAUTI prevention interventions. We found that the previously named stage 1 (catheter placement) is better described in 2 stages: stage 0, avoid catheter if possible, and stage 1, ensure aseptic placement. Additionally, we tailored the model to include actionable language, describing ways to disrupt the life cycle. Finally, we added a component to represent interventions to improve implementation and sustainability, such as auditing compliance and timely feedback to clinicians. Thus, we introduce a new conceptual model, “Disrupting the Life Cycle of a Catheter” (Figure 2)

Central Vascular Catheter Interventional Study Results

Characteristics of Included Central Vascular Catheter Infection Studies

Of the 102 central vascular catheter (CVC) studies that met the inclusion criteria (reporting outcomes for 105 intervention cohorts), 59 studies^{10,14,16,24-27,38-89} reporting outcomes for 61 intervention cohorts were performed in the US. Study designs included 14 randomized controlled trials (RCTs)^{48,64,68,74,79,90-98} and 88 before–after studies (Appendix Table 1). ^{10,14,16,24-27,33,38-47,49-63,69-73,75-78,80-89,99-131} Many RCTs evaluated antimicrobial products (CVCs, hubs, bathing) as interventions,^{48,68,74,90-95,97,98} but a few RCTs studied interventions^64,79,93 impacting catheter care or use (Appendix Table 1). Fifty-one studies took place in tertiary care hospitals and 55 in academic hospitals. Thirty-one studies were multicenter; the largest included 792 hospitals and 1071 ICUs.²⁴ ICU bed size ranged from 5 to 59.

CVC Study Outcomes

Sixty-three studies reported CLABSI outcomes, and 39 reported CRBSI outcomes (Table 2). Many studies had preintervention or control rates above the 2013 NHSN 75th percentiles,²² which varied by ICU type. Preintervention or control infection rates per 1000 catheter days varied widely (means: CLABSI 7.5, CRBSI 6.3); US studies reported ranges of 1.1 to 12.1 CLABSI and 1.2 to 11.0 CRBSI per 1000 catheter days; non-US studies reported ranges of 1.4 to 45.9 CLABSI and 1.6 to 22.7 CRBSI per 1000 catheter days. Postintervention rates varied widely, with overall means of 2.8 CLABSI and 2.5 CRBSI per 1000 catheter days, including US study ranges of 0 to 8.9 CLABSI and 0 to 5.4 CRBSI, and non-US study ranges of 0 to 17.1 CLABSI and 0 to 15.9 CRBSI.

CVC Interventions

CVC study interventions are summarized in Table 1, categorized by catheter life cycle component (Figure 2). Thirty-two included studies used a single intervention to prevent CVC infection. Interventions to avoid placement when possible were infrequent. Insertion-stage interventions were common and included avoiding the femoral site during placement, ensuring maximal sterile barriers, and chlorhexidine skin preparation. Standardizing basic products for central line insertion was often done by providing ICUs with a CLABSI insertion kit or stocked cart. In some studies, this was implemented prior to the intervention, and in others, the kit or cart itself was the intervention. Maintenance-stage interventions included scrubbing the hub prior to use, replacing wet or soiled dressings, accessing the catheter with sterile devices, and performing aseptic dressing changes. A recent systematic review and meta-analysis of CVC infection prevention studies indicated that implementing care bundles and/or checklists appears to yield stronger risk reductions than interventions without these components.¹³² The most common catheter removal interventions were daily audits of line removal and CLABSI rounds focused on ongoing catheter necessity.

Common implementation and sustainability interventions included outcome surveillance, such as feedback on CLABSI, and socio-adaptive interventions to prompt improvements in patient safety culture. Process and outcome surveillance as interventions were implemented in about one-quarter of the studies reviewed (AppendixTable 1).

CAUTI Interventional Study Results

Characteristics of Included CAUTI Studies

Of the 28 CAUTI studies that met the inclusion criteria (reporting outcomes for 30 intervention cohorts), 14 studies (reporting outcomes for 16 intervention cohorts) were performed in the US.^{28,34,53,66,68,133-141} Study designs included 2 RCTs (focused on urinary catheter avoidance or removal¹⁴² and chlorhexidine bathing⁶⁸) and 26 nonrandomized, before–after studies^{28,30,33,34,53,66,109,114-116,133-141,143-149} (Appendix Table 1). The number of hospitals per study varied from 1 to 53, with the majority being single-hospital interventions.

CAUTI Study Outcomes

All 28 studies reported CAUTIs per 1000 catheter days for both intervention and comparison groups (Table 2). Preintervention or control CAUTI rates varied widely, with an overall mean of 12.5 CAUTIs per 1000 catheter days; US studies reported a range from 1.4 to 15.8 CAUTIs per 1000 catheter days; non-US studies reported a range from 0.8 to 90.1 CAUTIs per 1000 catheter days. Many studies had preintervention or control rates above the 2013 NHSN 75th percentiles.²² Postintervention CAUTI rates varied widely, with an overall mean of 7.0 CAUTIs per 1000 catheter days, including a US study range from 0 to 11.2 and a non-US study range from 1.9 to 65.7.

Overall (Table 2), 27 of the 30 intervention cohorts described in the 28 studies reported fewer CAUTIs, including all ICU types. Lower postintervention CAUTI rates were reported in 25 studies, with a mean 49.4% reduction, including 11 statistically significant reductions; many studies did not report the level of statistical significance or described inadequate power to detect a significant change (Table 2).

Urinary catheter utilization rates were reported for 11 studies (Table 2). A decreased urinary catheter utilization rate was reported in 7 studies (4 with statistically signficiant reductions), with a mean 16% reduction (Table 2). Other outcomes included cost savings, the potential for unintended negative outcomes, and clinician compliance with intervention components. Positive cost savings were reported in 5 studies.^{30,34,133,141,149}

CAUTI Interventions

Of the 28 included CAUTI prevention studies, only 5 studied single interventions. Interventions were categorized in Table 1 by “life cycle” stages or as interventions to improve implementation and sustainability (Figure 2). Interventions to restrict indwelling urinary catheter use were common, including creating lists of approved indications selected by unit or hospital policy and requiring catheter orders with approved indications. Eight studies published approved indication lists.^{28,34,133-135,138,142,146} Although several studies describe the encouragement and use of bladder scanners and urinary catheter alternatives, none described purchasing these catheter alternatives.

Interventions to avoid indwelling urinary catheters included education about external catheters,^{28,34,109,133,140,144-146} urinary retention protocols,^{34,144,135,141} and bladder scanner simulation training.¹³³ Interventions to improve aseptic insertion^{28,34,66,109,116,139-141-143-146,150} and maintenance care^{28,34,66,109,116,133,135,136,139-141,143-146,150} of urinary catheters were common. Four studies used a standardized urinary catheter kit or cart,^{28,34,139,142} and 2 studies used a commercial urinary catheter securement device.^34,140 A CAUTI bundle checklist in daily patient care rounds was tested in 3 studies (Table 1).^66,136,150 Reminder and stop order strategies, with the potential to reduce CAUTI rates by >50%,¹⁵¹ were included in 15 studies, with inteventions such as nurse-empowered stop orders. Several implementation and sustainability interventions were described, including socio-adaptive strategies such as holding multidisciplinary meetings to obtain unit or clinician feedback to inform design and improve buy-in and providing frequent feedback to ICU clinicians, including audits of catheter use appropriateness and catheter-associated infections.

This extensive literature review yielded a large body of literature demonstrating success in preventing CLABSI and CAUTI in all types of adult ICUs, including in general medical and surgical ICUs and in specialized units with historically higher rates, such as trauma, burn, and neurosurgical. Reported reductions in catheter infections were impressive (>65% for CLABSI or CRBSI and nearly 50% for CAUTI), though several studies had limited power to detect statistical significance. DURs were reported more rarely (particularly for vascular catheters) and often without power to detect statistical significance. Nevertheless, 7 studies reported reduced urinary catheter use (16% mean reduction), which would be anticipated to be clinically significant.

The conceptual model introduced for “Disrupting the Life Cycle of a Catheter” (Figure 2) can be a helpful tool for hospitalists and intensivists to assess and prioritize potential strategies for reducing catheter-associated infections. This study’s results indicate that CLABSI prevention studies often used interventions that optimize best practices during aseptic insertion and maintenance, but few studies emphasized reducing inappropriate central line use. Conversely, CAUTI prevention often targeted avoiding placement and prompting the removal of urinary catheters, with fewer studies evaluating innovative products or technical skill advancement for aseptic insertion or maintenance, though educational interventions to standardize aseptic catheter use were common. Recently, recommendations for reducing the inappropriate use of urinary catheters and intravenous catheters, including scenarios common in ICUs, were developed by using the rigorous RAND/UCLA Appropriateness Method^152,153; these resources may be helpful to hospitalists designing and implementing interventions to reduce catheter use.

In reviewing the US studies of 5 units demonstrating the greatest success in preventing CLABSI^{56,62,65,78,83} and CAUTI,^28,34,66,134 several shared features emerged. Interventions that addressed multiple steps within the life cycle of a catheter (avoidance, insertion, maintenance, and removal) were common. Previous work has shown that assuring compliance in infection prevention efforts is a key to success,¹⁵⁴ and in both CLABSI and CAUTI studies, auditing was included in these successful interventions. Specifically for CLABSI, the checklist, a central quality improvement tool, was frequently associated with success. Unique to CAUTI, engaging a multidisciplinary team including nurse leadership seemed critical to optimize implementation and sustainability efforts. In addition, a focus on stage 3 (removal), including protocols to remove by default, was associated with success in CAUTI studies.

Our review was limited by a frequent lack of reporting of statistical significance or by inadequate power to detect a significant change and great variety. The ability to compare the impact of specific interventions is limited because studies varied greatly with respect to the type of intervention, duration of data collection, and outcomes assessed. We also anticipate that successful interventions are more likely to be published than are trials without success. Strengths include the use of a rigorous search process and the inclusion and review of several types of interventions implemented in ICUs.

In conclusion, despite high catheter use in ICUs, the literature includes many successful interventions for the prevention of vascular and urinary catheter infections in multiple ICU types. This review indicates that targeting multiple steps within the life cycle of a catheter, particularly when combined with interventions to optimize implementation and sustainability, can improve success in reducing CLABSI and CAUTI in the ICU.

Acknowledgments

The authors thank all members of the National Project Team for the AHRQ Safety Program for Intensive Care Units: Preventing CLABSI and CAUTI.

Disclosure

Agency for Healthcare Research and Quality (AHRQ) contract #HHSP233201500016I/HHSP23337002T provided funding for this study. J.M.’s other research is funded by AHRQ (2R01HS018334-04), the NIH-LRP program, the VA National Center for Patient Safety, VA Ann Arbor Patient Safety Center of Inquiry, the Health Research and Educational Trust, American Hospital Association and the Centers for Disease Control and Prevention. The findings and conclusions in this report are those of the authors and do not necessarily represent those of the sponsor, the Agency for Healthcare Research and Quality, or the US Department of Veterans Affairs. All authors report no conflicts of interest relevant to this article.

Central line–associated bloodstream infection (CLABSI) and catheter-associated urinary tract infection (CAUTI) are morbid and expensive healthcare-associated infections (HAIs).^1-8 While these HAIs are prevalent in intensive care units (ICUs) and general wards, most of the research, prevention efforts, and financial penalties have been focused in the ICU.^9,10 For hospitalists, who are taking a larger role in caring for the critically ill,^11,12 it is optimal to understand best preventive practices.

There has been a national puTash to standardize procedures and products to prevent CLABSI and CAUTI.^2,13-16 CLABSI has transitioned from a common ICU complication to a “never event.” Success has been reflected in the prevention of 25,000 CLABSIs over the last decade, translating to a 58% reduction in infections, with 6000 deaths prevented and $414 million saved.² CLABSI prevention principles have been applied to CAUTI prevention (ie, aseptic insertion, maintenance care, prompting removal) but with slower adoption¹⁷ and fewer dramatic CAUTI reductions,¹⁸ due in part to weaker recognition¹⁹ of CAUTI as a serious clinical event, despite its morbidity²⁰ and cost.²¹

Despite recent improvements in preventing HAIs, there is a marked variability in how hospitals perform in preventing these infections.²² To inform infection prevention strategies for a large-scale implementation project funded by the Agency for Healthcare Research and Quality and focused on ICUs with persistently elevated CLABSI and/or CAUTI rates,²³ we performed a systematic search of interventions to prevent CLABSI and CAUTI in the ICU setting. This evidence was synthesized to help units select and prioritize interventions to prevent these HAIs.

Literature Search Strategy

We performed a systematic search to identify CLABSI and CAUTI prevention studies and synthesized findings using a narrative review process. Using criteria developed and refined from seminal articles on the topic,^10,14,24-34 we searched the PubMed and Cochrane databases from their inception to October of 2015 using Medical Subject Headings (MeSHs) for “central venous catheters,” “CLABSI,” “central line associated bloodstream infection,” “catheter related bloodstream infection,” “intravascular devices,” “urinary catheterization,” “urinary catheters,” “urinary tract infections,” “CAUTI,” and “catheter associated urinary tract infections” and filtered for articles containing the MeSHs “intensive care unit” and “ICU.” Supplemental Figure 1 details the search, yielding 102 studies for CLABSI and 28 studies for CAUTI, including 7 studies with CLABSI and CAUTI interventions.

Eligibility Criteria Review

Study Design

We included randomized and nonrandomized studies that implemented at least 1 intervention to prevent CLABSI or CAUTI in an adult ICU setting and reported the preintervention or control group data to compare with the postintervention data. We excluded general ward, outpatient/ambulatory, and neonatal/pediatric settings. Interventions to prevent CLABSI or CAUTI were included. We excluded interventions focused on diagnosis or treatment or those that lacked adequate description of the intervention for replication. Studies with interventions that are no longer standard of care in the United States (US) were excluded, as were studies not available in English.

Outcomes

Primary Outcomes for Central Vascular Catheter Infection

• CLABSI: A lab-confirmed bloodstream infection in a patient who has had a central line for at least 48 hours on the date of the development of the bloodstream infection and without another known source of infection. We included studies that reported CLABSIs per 1000 central line days or those that provided data to permit calculation of this ratio. This measure is similar to current National Healthcare Safety Network (NHSN) surveillance definitions.²²
• Catheter-related bloodstream infection (CRBSI): A lab-confirmed bloodstream infection attributed to an intravascular catheter by a quantitative culture of the catheter tip or by differences in growth between catheter and peripheral venipuncture blood culture specimens.³⁵ This microbiologic definition of a central line bloodstream infection was often used prior to NHSN reporting, with rates provided as the number of CRBSIs per 1000 central line days.

Primary Outcome for Urinary Catheter Infection

• CAUTI: Urinary tract infection occurring in patients during or after the recent use of an indwelling urinary catheter. We included studies that reported CAUTIs per 1000 urinary catheter days or those that provided data to permit calculation of this ratio (similar to the current NHSN surveillance definitions).²² We excluded studies where CAUTI was defined as bacteriuria alone, without symptoms.

Secondary Outcomes

• Central line utilization ratio: The device utilization ratio (DUR) measure of central line use is calculated as central line days divided by patient days.
• Urinary catheter utilization ratio: The DUR measure of urinary catheter use is calculated as indwelling urinary catheter days divided by patient days, as used in NHSN surveillance, excluding other catheter types.²² We excluded other measures of urinary catheter use because of a large variation in definitions, which limits the ability to compare measures across studies.

Data Synthesis and Analysis

Information on the ICU and intervention type, intervention components, outcomes, and whether interventions were in use prior to the study was abstracted by CAUTI and CLABSI experts (JM and PKP) and confirmed by a second author.

We compared interventions found in the literature to components of the previously published urinary catheter “life cycle,” a conceptual model used to organize and prioritize interventions for a reduction in CAUTI (Figure 1).³⁶

Conceptual Model for Disrupting the Life Cycle of a Catheter

Our data analysis demonstrated that components of the urinary catheter life cycle (Figure 1) were useful and could be applied to vascular catheters, but changes were needed to make the model more valuable to hospitalists implementing CLABSI and CAUTI prevention interventions. We found that the previously named stage 1 (catheter placement) is better described in 2 stages: stage 0, avoid catheter if possible, and stage 1, ensure aseptic placement. Additionally, we tailored the model to include actionable language, describing ways to disrupt the life cycle. Finally, we added a component to represent interventions to improve implementation and sustainability, such as auditing compliance and timely feedback to clinicians. Thus, we introduce a new conceptual model, “Disrupting the Life Cycle of a Catheter” (Figure 2)

Central Vascular Catheter Interventional Study Results

Characteristics of Included Central Vascular Catheter Infection Studies

Of the 102 central vascular catheter (CVC) studies that met the inclusion criteria (reporting outcomes for 105 intervention cohorts), 59 studies^{10,14,16,24-27,38-89} reporting outcomes for 61 intervention cohorts were performed in the US. Study designs included 14 randomized controlled trials (RCTs)^{48,64,68,74,79,90-98} and 88 before–after studies (Appendix Table 1). ^{10,14,16,24-27,33,38-47,49-63,69-73,75-78,80-89,99-131} Many RCTs evaluated antimicrobial products (CVCs, hubs, bathing) as interventions,^{48,68,74,90-95,97,98} but a few RCTs studied interventions^64,79,93 impacting catheter care or use (Appendix Table 1). Fifty-one studies took place in tertiary care hospitals and 55 in academic hospitals. Thirty-one studies were multicenter; the largest included 792 hospitals and 1071 ICUs.²⁴ ICU bed size ranged from 5 to 59.

CVC Study Outcomes

Sixty-three studies reported CLABSI outcomes, and 39 reported CRBSI outcomes (Table 2). Many studies had preintervention or control rates above the 2013 NHSN 75th percentiles,²² which varied by ICU type. Preintervention or control infection rates per 1000 catheter days varied widely (means: CLABSI 7.5, CRBSI 6.3); US studies reported ranges of 1.1 to 12.1 CLABSI and 1.2 to 11.0 CRBSI per 1000 catheter days; non-US studies reported ranges of 1.4 to 45.9 CLABSI and 1.6 to 22.7 CRBSI per 1000 catheter days. Postintervention rates varied widely, with overall means of 2.8 CLABSI and 2.5 CRBSI per 1000 catheter days, including US study ranges of 0 to 8.9 CLABSI and 0 to 5.4 CRBSI, and non-US study ranges of 0 to 17.1 CLABSI and 0 to 15.9 CRBSI.

CVC Interventions

CVC study interventions are summarized in Table 1, categorized by catheter life cycle component (Figure 2). Thirty-two included studies used a single intervention to prevent CVC infection. Interventions to avoid placement when possible were infrequent. Insertion-stage interventions were common and included avoiding the femoral site during placement, ensuring maximal sterile barriers, and chlorhexidine skin preparation. Standardizing basic products for central line insertion was often done by providing ICUs with a CLABSI insertion kit or stocked cart. In some studies, this was implemented prior to the intervention, and in others, the kit or cart itself was the intervention. Maintenance-stage interventions included scrubbing the hub prior to use, replacing wet or soiled dressings, accessing the catheter with sterile devices, and performing aseptic dressing changes. A recent systematic review and meta-analysis of CVC infection prevention studies indicated that implementing care bundles and/or checklists appears to yield stronger risk reductions than interventions without these components.¹³² The most common catheter removal interventions were daily audits of line removal and CLABSI rounds focused on ongoing catheter necessity.

Common implementation and sustainability interventions included outcome surveillance, such as feedback on CLABSI, and socio-adaptive interventions to prompt improvements in patient safety culture. Process and outcome surveillance as interventions were implemented in about one-quarter of the studies reviewed (AppendixTable 1).

CAUTI Interventional Study Results

Characteristics of Included CAUTI Studies

Of the 28 CAUTI studies that met the inclusion criteria (reporting outcomes for 30 intervention cohorts), 14 studies (reporting outcomes for 16 intervention cohorts) were performed in the US.^{28,34,53,66,68,133-141} Study designs included 2 RCTs (focused on urinary catheter avoidance or removal¹⁴² and chlorhexidine bathing⁶⁸) and 26 nonrandomized, before–after studies^{28,30,33,34,53,66,109,114-116,133-141,143-149} (Appendix Table 1). The number of hospitals per study varied from 1 to 53, with the majority being single-hospital interventions.

CAUTI Study Outcomes

All 28 studies reported CAUTIs per 1000 catheter days for both intervention and comparison groups (Table 2). Preintervention or control CAUTI rates varied widely, with an overall mean of 12.5 CAUTIs per 1000 catheter days; US studies reported a range from 1.4 to 15.8 CAUTIs per 1000 catheter days; non-US studies reported a range from 0.8 to 90.1 CAUTIs per 1000 catheter days. Many studies had preintervention or control rates above the 2013 NHSN 75th percentiles.²² Postintervention CAUTI rates varied widely, with an overall mean of 7.0 CAUTIs per 1000 catheter days, including a US study range from 0 to 11.2 and a non-US study range from 1.9 to 65.7.

Overall (Table 2), 27 of the 30 intervention cohorts described in the 28 studies reported fewer CAUTIs, including all ICU types. Lower postintervention CAUTI rates were reported in 25 studies, with a mean 49.4% reduction, including 11 statistically significant reductions; many studies did not report the level of statistical significance or described inadequate power to detect a significant change (Table 2).

Urinary catheter utilization rates were reported for 11 studies (Table 2). A decreased urinary catheter utilization rate was reported in 7 studies (4 with statistically signficiant reductions), with a mean 16% reduction (Table 2). Other outcomes included cost savings, the potential for unintended negative outcomes, and clinician compliance with intervention components. Positive cost savings were reported in 5 studies.^{30,34,133,141,149}

CAUTI Interventions

Of the 28 included CAUTI prevention studies, only 5 studied single interventions. Interventions were categorized in Table 1 by “life cycle” stages or as interventions to improve implementation and sustainability (Figure 2). Interventions to restrict indwelling urinary catheter use were common, including creating lists of approved indications selected by unit or hospital policy and requiring catheter orders with approved indications. Eight studies published approved indication lists.^{28,34,133-135,138,142,146} Although several studies describe the encouragement and use of bladder scanners and urinary catheter alternatives, none described purchasing these catheter alternatives.

Interventions to avoid indwelling urinary catheters included education about external catheters,^{28,34,109,133,140,144-146} urinary retention protocols,^{34,144,135,141} and bladder scanner simulation training.¹³³ Interventions to improve aseptic insertion^{28,34,66,109,116,139-141-143-146,150} and maintenance care^{28,34,66,109,116,133,135,136,139-141,143-146,150} of urinary catheters were common. Four studies used a standardized urinary catheter kit or cart,^{28,34,139,142} and 2 studies used a commercial urinary catheter securement device.^34,140 A CAUTI bundle checklist in daily patient care rounds was tested in 3 studies (Table 1).^66,136,150 Reminder and stop order strategies, with the potential to reduce CAUTI rates by >50%,¹⁵¹ were included in 15 studies, with inteventions such as nurse-empowered stop orders. Several implementation and sustainability interventions were described, including socio-adaptive strategies such as holding multidisciplinary meetings to obtain unit or clinician feedback to inform design and improve buy-in and providing frequent feedback to ICU clinicians, including audits of catheter use appropriateness and catheter-associated infections.

This extensive literature review yielded a large body of literature demonstrating success in preventing CLABSI and CAUTI in all types of adult ICUs, including in general medical and surgical ICUs and in specialized units with historically higher rates, such as trauma, burn, and neurosurgical. Reported reductions in catheter infections were impressive (>65% for CLABSI or CRBSI and nearly 50% for CAUTI), though several studies had limited power to detect statistical significance. DURs were reported more rarely (particularly for vascular catheters) and often without power to detect statistical significance. Nevertheless, 7 studies reported reduced urinary catheter use (16% mean reduction), which would be anticipated to be clinically significant.

The conceptual model introduced for “Disrupting the Life Cycle of a Catheter” (Figure 2) can be a helpful tool for hospitalists and intensivists to assess and prioritize potential strategies for reducing catheter-associated infections. This study’s results indicate that CLABSI prevention studies often used interventions that optimize best practices during aseptic insertion and maintenance, but few studies emphasized reducing inappropriate central line use. Conversely, CAUTI prevention often targeted avoiding placement and prompting the removal of urinary catheters, with fewer studies evaluating innovative products or technical skill advancement for aseptic insertion or maintenance, though educational interventions to standardize aseptic catheter use were common. Recently, recommendations for reducing the inappropriate use of urinary catheters and intravenous catheters, including scenarios common in ICUs, were developed by using the rigorous RAND/UCLA Appropriateness Method^152,153; these resources may be helpful to hospitalists designing and implementing interventions to reduce catheter use.

In reviewing the US studies of 5 units demonstrating the greatest success in preventing CLABSI^{56,62,65,78,83} and CAUTI,^28,34,66,134 several shared features emerged. Interventions that addressed multiple steps within the life cycle of a catheter (avoidance, insertion, maintenance, and removal) were common. Previous work has shown that assuring compliance in infection prevention efforts is a key to success,¹⁵⁴ and in both CLABSI and CAUTI studies, auditing was included in these successful interventions. Specifically for CLABSI, the checklist, a central quality improvement tool, was frequently associated with success. Unique to CAUTI, engaging a multidisciplinary team including nurse leadership seemed critical to optimize implementation and sustainability efforts. In addition, a focus on stage 3 (removal), including protocols to remove by default, was associated with success in CAUTI studies.

Our review was limited by a frequent lack of reporting of statistical significance or by inadequate power to detect a significant change and great variety. The ability to compare the impact of specific interventions is limited because studies varied greatly with respect to the type of intervention, duration of data collection, and outcomes assessed. We also anticipate that successful interventions are more likely to be published than are trials without success. Strengths include the use of a rigorous search process and the inclusion and review of several types of interventions implemented in ICUs.

In conclusion, despite high catheter use in ICUs, the literature includes many successful interventions for the prevention of vascular and urinary catheter infections in multiple ICU types. This review indicates that targeting multiple steps within the life cycle of a catheter, particularly when combined with interventions to optimize implementation and sustainability, can improve success in reducing CLABSI and CAUTI in the ICU.

Acknowledgments

The authors thank all members of the National Project Team for the AHRQ Safety Program for Intensive Care Units: Preventing CLABSI and CAUTI.

Disclosure

Agency for Healthcare Research and Quality (AHRQ) contract #HHSP233201500016I/HHSP23337002T provided funding for this study. J.M.’s other research is funded by AHRQ (2R01HS018334-04), the NIH-LRP program, the VA National Center for Patient Safety, VA Ann Arbor Patient Safety Center of Inquiry, the Health Research and Educational Trust, American Hospital Association and the Centers for Disease Control and Prevention. The findings and conclusions in this report are those of the authors and do not necessarily represent those of the sponsor, the Agency for Healthcare Research and Quality, or the US Department of Veterans Affairs. All authors report no conflicts of interest relevant to this article.

Central line–associated bloodstream infection (CLABSI) and catheter-associated urinary tract infection (CAUTI) are morbid and expensive healthcare-associated infections (HAIs).^1-8 While these HAIs are prevalent in intensive care units (ICUs) and general wards, most of the research, prevention efforts, and financial penalties have been focused in the ICU.^9,10 For hospitalists, who are taking a larger role in caring for the critically ill,^11,12 it is optimal to understand best preventive practices.

There has been a national puTash to standardize procedures and products to prevent CLABSI and CAUTI.^2,13-16 CLABSI has transitioned from a common ICU complication to a “never event.” Success has been reflected in the prevention of 25,000 CLABSIs over the last decade, translating to a 58% reduction in infections, with 6000 deaths prevented and $414 million saved.² CLABSI prevention principles have been applied to CAUTI prevention (ie, aseptic insertion, maintenance care, prompting removal) but with slower adoption¹⁷ and fewer dramatic CAUTI reductions,¹⁸ due in part to weaker recognition¹⁹ of CAUTI as a serious clinical event, despite its morbidity²⁰ and cost.²¹

Despite recent improvements in preventing HAIs, there is a marked variability in how hospitals perform in preventing these infections.²² To inform infection prevention strategies for a large-scale implementation project funded by the Agency for Healthcare Research and Quality and focused on ICUs with persistently elevated CLABSI and/or CAUTI rates,²³ we performed a systematic search of interventions to prevent CLABSI and CAUTI in the ICU setting. This evidence was synthesized to help units select and prioritize interventions to prevent these HAIs.

Literature Search Strategy

We performed a systematic search to identify CLABSI and CAUTI prevention studies and synthesized findings using a narrative review process. Using criteria developed and refined from seminal articles on the topic,^10,14,24-34 we searched the PubMed and Cochrane databases from their inception to October of 2015 using Medical Subject Headings (MeSHs) for “central venous catheters,” “CLABSI,” “central line associated bloodstream infection,” “catheter related bloodstream infection,” “intravascular devices,” “urinary catheterization,” “urinary catheters,” “urinary tract infections,” “CAUTI,” and “catheter associated urinary tract infections” and filtered for articles containing the MeSHs “intensive care unit” and “ICU.” Supplemental Figure 1 details the search, yielding 102 studies for CLABSI and 28 studies for CAUTI, including 7 studies with CLABSI and CAUTI interventions.

Eligibility Criteria Review

Study Design

We included randomized and nonrandomized studies that implemented at least 1 intervention to prevent CLABSI or CAUTI in an adult ICU setting and reported the preintervention or control group data to compare with the postintervention data. We excluded general ward, outpatient/ambulatory, and neonatal/pediatric settings. Interventions to prevent CLABSI or CAUTI were included. We excluded interventions focused on diagnosis or treatment or those that lacked adequate description of the intervention for replication. Studies with interventions that are no longer standard of care in the United States (US) were excluded, as were studies not available in English.

Outcomes

Primary Outcomes for Central Vascular Catheter Infection

• CLABSI: A lab-confirmed bloodstream infection in a patient who has had a central line for at least 48 hours on the date of the development of the bloodstream infection and without another known source of infection. We included studies that reported CLABSIs per 1000 central line days or those that provided data to permit calculation of this ratio. This measure is similar to current National Healthcare Safety Network (NHSN) surveillance definitions.²²
• Catheter-related bloodstream infection (CRBSI): A lab-confirmed bloodstream infection attributed to an intravascular catheter by a quantitative culture of the catheter tip or by differences in growth between catheter and peripheral venipuncture blood culture specimens.³⁵ This microbiologic definition of a central line bloodstream infection was often used prior to NHSN reporting, with rates provided as the number of CRBSIs per 1000 central line days.

Primary Outcome for Urinary Catheter Infection

• CAUTI: Urinary tract infection occurring in patients during or after the recent use of an indwelling urinary catheter. We included studies that reported CAUTIs per 1000 urinary catheter days or those that provided data to permit calculation of this ratio (similar to the current NHSN surveillance definitions).²² We excluded studies where CAUTI was defined as bacteriuria alone, without symptoms.

Secondary Outcomes

• Central line utilization ratio: The device utilization ratio (DUR) measure of central line use is calculated as central line days divided by patient days.
• Urinary catheter utilization ratio: The DUR measure of urinary catheter use is calculated as indwelling urinary catheter days divided by patient days, as used in NHSN surveillance, excluding other catheter types.²² We excluded other measures of urinary catheter use because of a large variation in definitions, which limits the ability to compare measures across studies.

Data Synthesis and Analysis

Information on the ICU and intervention type, intervention components, outcomes, and whether interventions were in use prior to the study was abstracted by CAUTI and CLABSI experts (JM and PKP) and confirmed by a second author.

We compared interventions found in the literature to components of the previously published urinary catheter “life cycle,” a conceptual model used to organize and prioritize interventions for a reduction in CAUTI (Figure 1).³⁶

Conceptual Model for Disrupting the Life Cycle of a Catheter

Our data analysis demonstrated that components of the urinary catheter life cycle (Figure 1) were useful and could be applied to vascular catheters, but changes were needed to make the model more valuable to hospitalists implementing CLABSI and CAUTI prevention interventions. We found that the previously named stage 1 (catheter placement) is better described in 2 stages: stage 0, avoid catheter if possible, and stage 1, ensure aseptic placement. Additionally, we tailored the model to include actionable language, describing ways to disrupt the life cycle. Finally, we added a component to represent interventions to improve implementation and sustainability, such as auditing compliance and timely feedback to clinicians. Thus, we introduce a new conceptual model, “Disrupting the Life Cycle of a Catheter” (Figure 2)

Central Vascular Catheter Interventional Study Results

Characteristics of Included Central Vascular Catheter Infection Studies

Of the 102 central vascular catheter (CVC) studies that met the inclusion criteria (reporting outcomes for 105 intervention cohorts), 59 studies^{10,14,16,24-27,38-89} reporting outcomes for 61 intervention cohorts were performed in the US. Study designs included 14 randomized controlled trials (RCTs)^{48,64,68,74,79,90-98} and 88 before–after studies (Appendix Table 1). ^{10,14,16,24-27,33,38-47,49-63,69-73,75-78,80-89,99-131} Many RCTs evaluated antimicrobial products (CVCs, hubs, bathing) as interventions,^{48,68,74,90-95,97,98} but a few RCTs studied interventions^64,79,93 impacting catheter care or use (Appendix Table 1). Fifty-one studies took place in tertiary care hospitals and 55 in academic hospitals. Thirty-one studies were multicenter; the largest included 792 hospitals and 1071 ICUs.²⁴ ICU bed size ranged from 5 to 59.

CVC Study Outcomes

Sixty-three studies reported CLABSI outcomes, and 39 reported CRBSI outcomes (Table 2). Many studies had preintervention or control rates above the 2013 NHSN 75th percentiles,²² which varied by ICU type. Preintervention or control infection rates per 1000 catheter days varied widely (means: CLABSI 7.5, CRBSI 6.3); US studies reported ranges of 1.1 to 12.1 CLABSI and 1.2 to 11.0 CRBSI per 1000 catheter days; non-US studies reported ranges of 1.4 to 45.9 CLABSI and 1.6 to 22.7 CRBSI per 1000 catheter days. Postintervention rates varied widely, with overall means of 2.8 CLABSI and 2.5 CRBSI per 1000 catheter days, including US study ranges of 0 to 8.9 CLABSI and 0 to 5.4 CRBSI, and non-US study ranges of 0 to 17.1 CLABSI and 0 to 15.9 CRBSI.

CVC Interventions

CVC study interventions are summarized in Table 1, categorized by catheter life cycle component (Figure 2). Thirty-two included studies used a single intervention to prevent CVC infection. Interventions to avoid placement when possible were infrequent. Insertion-stage interventions were common and included avoiding the femoral site during placement, ensuring maximal sterile barriers, and chlorhexidine skin preparation. Standardizing basic products for central line insertion was often done by providing ICUs with a CLABSI insertion kit or stocked cart. In some studies, this was implemented prior to the intervention, and in others, the kit or cart itself was the intervention. Maintenance-stage interventions included scrubbing the hub prior to use, replacing wet or soiled dressings, accessing the catheter with sterile devices, and performing aseptic dressing changes. A recent systematic review and meta-analysis of CVC infection prevention studies indicated that implementing care bundles and/or checklists appears to yield stronger risk reductions than interventions without these components.¹³² The most common catheter removal interventions were daily audits of line removal and CLABSI rounds focused on ongoing catheter necessity.

Common implementation and sustainability interventions included outcome surveillance, such as feedback on CLABSI, and socio-adaptive interventions to prompt improvements in patient safety culture. Process and outcome surveillance as interventions were implemented in about one-quarter of the studies reviewed (AppendixTable 1).

CAUTI Interventional Study Results

Characteristics of Included CAUTI Studies

Of the 28 CAUTI studies that met the inclusion criteria (reporting outcomes for 30 intervention cohorts), 14 studies (reporting outcomes for 16 intervention cohorts) were performed in the US.^{28,34,53,66,68,133-141} Study designs included 2 RCTs (focused on urinary catheter avoidance or removal¹⁴² and chlorhexidine bathing⁶⁸) and 26 nonrandomized, before–after studies^{28,30,33,34,53,66,109,114-116,133-141,143-149} (Appendix Table 1). The number of hospitals per study varied from 1 to 53, with the majority being single-hospital interventions.

CAUTI Study Outcomes

All 28 studies reported CAUTIs per 1000 catheter days for both intervention and comparison groups (Table 2). Preintervention or control CAUTI rates varied widely, with an overall mean of 12.5 CAUTIs per 1000 catheter days; US studies reported a range from 1.4 to 15.8 CAUTIs per 1000 catheter days; non-US studies reported a range from 0.8 to 90.1 CAUTIs per 1000 catheter days. Many studies had preintervention or control rates above the 2013 NHSN 75th percentiles.²² Postintervention CAUTI rates varied widely, with an overall mean of 7.0 CAUTIs per 1000 catheter days, including a US study range from 0 to 11.2 and a non-US study range from 1.9 to 65.7.

Overall (Table 2), 27 of the 30 intervention cohorts described in the 28 studies reported fewer CAUTIs, including all ICU types. Lower postintervention CAUTI rates were reported in 25 studies, with a mean 49.4% reduction, including 11 statistically significant reductions; many studies did not report the level of statistical significance or described inadequate power to detect a significant change (Table 2).

Urinary catheter utilization rates were reported for 11 studies (Table 2). A decreased urinary catheter utilization rate was reported in 7 studies (4 with statistically signficiant reductions), with a mean 16% reduction (Table 2). Other outcomes included cost savings, the potential for unintended negative outcomes, and clinician compliance with intervention components. Positive cost savings were reported in 5 studies.^{30,34,133,141,149}

CAUTI Interventions

Of the 28 included CAUTI prevention studies, only 5 studied single interventions. Interventions were categorized in Table 1 by “life cycle” stages or as interventions to improve implementation and sustainability (Figure 2). Interventions to restrict indwelling urinary catheter use were common, including creating lists of approved indications selected by unit or hospital policy and requiring catheter orders with approved indications. Eight studies published approved indication lists.^{28,34,133-135,138,142,146} Although several studies describe the encouragement and use of bladder scanners and urinary catheter alternatives, none described purchasing these catheter alternatives.

Interventions to avoid indwelling urinary catheters included education about external catheters,^{28,34,109,133,140,144-146} urinary retention protocols,^{34,144,135,141} and bladder scanner simulation training.¹³³ Interventions to improve aseptic insertion^{28,34,66,109,116,139-141-143-146,150} and maintenance care^{28,34,66,109,116,133,135,136,139-141,143-146,150} of urinary catheters were common. Four studies used a standardized urinary catheter kit or cart,^{28,34,139,142} and 2 studies used a commercial urinary catheter securement device.^34,140 A CAUTI bundle checklist in daily patient care rounds was tested in 3 studies (Table 1).^66,136,150 Reminder and stop order strategies, with the potential to reduce CAUTI rates by >50%,¹⁵¹ were included in 15 studies, with inteventions such as nurse-empowered stop orders. Several implementation and sustainability interventions were described, including socio-adaptive strategies such as holding multidisciplinary meetings to obtain unit or clinician feedback to inform design and improve buy-in and providing frequent feedback to ICU clinicians, including audits of catheter use appropriateness and catheter-associated infections.

This extensive literature review yielded a large body of literature demonstrating success in preventing CLABSI and CAUTI in all types of adult ICUs, including in general medical and surgical ICUs and in specialized units with historically higher rates, such as trauma, burn, and neurosurgical. Reported reductions in catheter infections were impressive (>65% for CLABSI or CRBSI and nearly 50% for CAUTI), though several studies had limited power to detect statistical significance. DURs were reported more rarely (particularly for vascular catheters) and often without power to detect statistical significance. Nevertheless, 7 studies reported reduced urinary catheter use (16% mean reduction), which would be anticipated to be clinically significant.

The conceptual model introduced for “Disrupting the Life Cycle of a Catheter” (Figure 2) can be a helpful tool for hospitalists and intensivists to assess and prioritize potential strategies for reducing catheter-associated infections. This study’s results indicate that CLABSI prevention studies often used interventions that optimize best practices during aseptic insertion and maintenance, but few studies emphasized reducing inappropriate central line use. Conversely, CAUTI prevention often targeted avoiding placement and prompting the removal of urinary catheters, with fewer studies evaluating innovative products or technical skill advancement for aseptic insertion or maintenance, though educational interventions to standardize aseptic catheter use were common. Recently, recommendations for reducing the inappropriate use of urinary catheters and intravenous catheters, including scenarios common in ICUs, were developed by using the rigorous RAND/UCLA Appropriateness Method^152,153; these resources may be helpful to hospitalists designing and implementing interventions to reduce catheter use.

In reviewing the US studies of 5 units demonstrating the greatest success in preventing CLABSI^{56,62,65,78,83} and CAUTI,^28,34,66,134 several shared features emerged. Interventions that addressed multiple steps within the life cycle of a catheter (avoidance, insertion, maintenance, and removal) were common. Previous work has shown that assuring compliance in infection prevention efforts is a key to success,¹⁵⁴ and in both CLABSI and CAUTI studies, auditing was included in these successful interventions. Specifically for CLABSI, the checklist, a central quality improvement tool, was frequently associated with success. Unique to CAUTI, engaging a multidisciplinary team including nurse leadership seemed critical to optimize implementation and sustainability efforts. In addition, a focus on stage 3 (removal), including protocols to remove by default, was associated with success in CAUTI studies.

Our review was limited by a frequent lack of reporting of statistical significance or by inadequate power to detect a significant change and great variety. The ability to compare the impact of specific interventions is limited because studies varied greatly with respect to the type of intervention, duration of data collection, and outcomes assessed. We also anticipate that successful interventions are more likely to be published than are trials without success. Strengths include the use of a rigorous search process and the inclusion and review of several types of interventions implemented in ICUs.

In conclusion, despite high catheter use in ICUs, the literature includes many successful interventions for the prevention of vascular and urinary catheter infections in multiple ICU types. This review indicates that targeting multiple steps within the life cycle of a catheter, particularly when combined with interventions to optimize implementation and sustainability, can improve success in reducing CLABSI and CAUTI in the ICU.

Acknowledgments

The authors thank all members of the National Project Team for the AHRQ Safety Program for Intensive Care Units: Preventing CLABSI and CAUTI.

Disclosure

Agency for Healthcare Research and Quality (AHRQ) contract #HHSP233201500016I/HHSP23337002T provided funding for this study. J.M.’s other research is funded by AHRQ (2R01HS018334-04), the NIH-LRP program, the VA National Center for Patient Safety, VA Ann Arbor Patient Safety Center of Inquiry, the Health Research and Educational Trust, American Hospital Association and the Centers for Disease Control and Prevention. The findings and conclusions in this report are those of the authors and do not necessarily represent those of the sponsor, the Agency for Healthcare Research and Quality, or the US Department of Veterans Affairs. All authors report no conflicts of interest relevant to this article.

Smells – of skin, breath, or bodily fluids – can, in some cases, reveal the presence of disease. This fact has led researchers to try to build an odor sensor that could make a fast, reliable diagnosis, and now the field may be on the verge of a breakthrough, according to a recent article in the New York Times.

In addition to various efforts in Austria, Switzerland, and Japan, an English manufacturer – Owlstone Medical – has been making headway with an odor analysis technology. It will be part of a National Health Service trial that will test the sensor for diagnosing lung cancer. The company also is conducting a trial using urine samples to detect colon cancer; its program allows changing the software to change what disease you detect.

Meanwhile, an Israeli chemical engineer, Hossam Haick, is using similar technology, with molecular receptors that have an affinity for certain biomarkers of disease found in the breath. Artificial intelligence allows the sensors to improve with each use, and a paper published last year showed that this system could distinguish among 17 different diseases with up to 86% accuracy.

And in the United States, researchers from the Monell Chemical Senses Center and the University of Pennsylvania are working on an odor sensor that detects ovarian cancer in samples of blood plasma. They chose plasma because it is less likely than breath or urine to be affected by other factors such as diet or environmental chemicals.

These technologies could be available to doctors in 3-5 years, experts say.

Reference

Murphy K. One Day, a Machine Will Smell Whether You’re Sick . New York Times. May 1, 2017. Accessed May 29, 2017.

Smells – of skin, breath, or bodily fluids – can, in some cases, reveal the presence of disease. This fact has led researchers to try to build an odor sensor that could make a fast, reliable diagnosis, and now the field may be on the verge of a breakthrough, according to a recent article in the New York Times.

In addition to various efforts in Austria, Switzerland, and Japan, an English manufacturer – Owlstone Medical – has been making headway with an odor analysis technology. It will be part of a National Health Service trial that will test the sensor for diagnosing lung cancer. The company also is conducting a trial using urine samples to detect colon cancer; its program allows changing the software to change what disease you detect.

Meanwhile, an Israeli chemical engineer, Hossam Haick, is using similar technology, with molecular receptors that have an affinity for certain biomarkers of disease found in the breath. Artificial intelligence allows the sensors to improve with each use, and a paper published last year showed that this system could distinguish among 17 different diseases with up to 86% accuracy.

And in the United States, researchers from the Monell Chemical Senses Center and the University of Pennsylvania are working on an odor sensor that detects ovarian cancer in samples of blood plasma. They chose plasma because it is less likely than breath or urine to be affected by other factors such as diet or environmental chemicals.

These technologies could be available to doctors in 3-5 years, experts say.

Reference

Murphy K. One Day, a Machine Will Smell Whether You’re Sick . New York Times. May 1, 2017. Accessed May 29, 2017.

Smells – of skin, breath, or bodily fluids – can, in some cases, reveal the presence of disease. This fact has led researchers to try to build an odor sensor that could make a fast, reliable diagnosis, and now the field may be on the verge of a breakthrough, according to a recent article in the New York Times.

In addition to various efforts in Austria, Switzerland, and Japan, an English manufacturer – Owlstone Medical – has been making headway with an odor analysis technology. It will be part of a National Health Service trial that will test the sensor for diagnosing lung cancer. The company also is conducting a trial using urine samples to detect colon cancer; its program allows changing the software to change what disease you detect.

Meanwhile, an Israeli chemical engineer, Hossam Haick, is using similar technology, with molecular receptors that have an affinity for certain biomarkers of disease found in the breath. Artificial intelligence allows the sensors to improve with each use, and a paper published last year showed that this system could distinguish among 17 different diseases with up to 86% accuracy.

And in the United States, researchers from the Monell Chemical Senses Center and the University of Pennsylvania are working on an odor sensor that detects ovarian cancer in samples of blood plasma. They chose plasma because it is less likely than breath or urine to be affected by other factors such as diet or environmental chemicals.

These technologies could be available to doctors in 3-5 years, experts say.

Reference

Murphy K. One Day, a Machine Will Smell Whether You’re Sick . New York Times. May 1, 2017. Accessed May 29, 2017.