The estimated prevalence of acute colonic diverticulitis in the United States appears to be on the rise, wrote Amir Qaseem, MD, and members of the ACP Clinical Guidelines Committee. “Approximately 200,000 hospitalizations for acute left-sided colonic diverticulitis occur in the United States each year, with annual costs of more than $8 billion. Timely and correct diagnosis of acute left-sided colonic diverticulitis is essential for the selection of the most appropriate management options.”
Diverticulitis is becoming increasingly common in patients treated by internal medicine physicians, according to the ACP, and the new clinical guidelines specify a course of treatment focused on outpatient management and minimal medications.
The guidelines, published in Annals of Internal Medicine, were based on a systematic review of evidence from studies published between Jan. 1, 1990, and June 1, 2020. Notably, right-sided diverticulitis was excluded because it is rare in Western countries and involves a different natural history and management options, the authors wrote.
In the guidelines, uncomplicated diverticulitis refers to localized inflammation, and complicated diverticulitis refers to “inflammation associated with an abscess, a phlegmon, a fistula, an obstruction, bleeding, or perforation.”
Guidance on diagnosis and management
In the first guideline,the authors provided three recommendations. First, they recommended that clinicians use abdominal CT imaging in cases of diagnostic uncertainty for patients with suspected acute left-sided colonic diverticulitis. The evidence showed that abdominal CT was associated with appropriate management in patients with suspected acute left-sided colonic diverticulitis, and that misdiagnosis with CT was rare.
Second, the authors of this guidance recommended management of most patients with acute left-sided colonic diverticulitis in an outpatient setting. Evidence showed that the risk for elective surgery and for recurrence were not significantly different based on inpatient or outpatient management.
The third recommendation advised clinicians to manage most patients without antibiotics. This recommendation was based on data showing no significant difference in quality of life at 3, 6, 12, or 24 months; no difference in diverticulitis-related complications; and no difference in the need for surgery in patients treated with antibiotics and those not treated with antibiotics.
All three recommendations are conditional, with low-certainty evidence, according to the authors.
Colonoscopy for diagnostic evaluation and interventions
In the second guideline,the authors advised clinicians to refer patients for a colonoscopy after an initial episode of complicated left-sided colonic diverticulitis if they have not had a recent colonoscopy.
Although acute diverticulitis is usually uncomplicated, approximately 12% of cases are considered complicated, and these patients may have a higher prevalence of colorectal cancer, the authors noted. This recommendation was conditional, with low-certainty evidence. Additional diagnostic colonoscopy is not needed for patients who are up to date on recommended colorectal cancer screening, according to this guideline.
A second recommendation, given as a strong recommendation with high-certainty evidence, advised against using mesalamine to prevent recurrent diverticulitis. Evidence showed that use of mesalamine at doses ranging from 1.2 g/day to 4.8 g/day made no difference in recurrent diverticulitis risk compared with placebo. Mesalamine has no demonstrated clinical benefits, and has been associated with epigastric pain, nausea, diarrhea, dizziness, rash, and renal and hepatic impairment, the authors wrote.
The third recommendation advised the discussion of elective surgery with patients with a history of uncomplicated diverticulitis that persists or recurs frequently. Surgery also may be an option for patients with complicated diverticulitis, according to the guideline. However, “this recommendation does not apply to patients with uncomplicated diverticulitis that is not persistent or frequently recurring,” the authors wrote.
The decision to pursue elective surgery should be informed and personalized according to potential benefits, harms, costs, and patient preferences, they said. This recommendation is conditional, with low-certainty evidence.
This new guideline was designed “to guide care based on the best available evidence and may not apply to all patients or individual clinical situations,” the authors emphasized. “It should not be used as a replacement for a clinician’s judgment.”