Ambulance Diversion Associated With Increased Heart Attack Mortality

SEATTLE – Patients having heart attacks are more likely to die if their nearest emergency department is temporarily refusing new patients, according to a study that linked heart attack outcomes to hospital diversion logs in four California counties, and that was presented at the annual research meeting of AcademyHealth.

Acute MI death rates are about 3% higher if the closest ED is on 12 or more hours of diversion on the day of the heart attack.

Treatment delays could be the reason, but patients in the study were typically accepted by another ED within a mile. Another possible explanation is that diverted patients were less likely to end up at EDs with readily available and potentially lifesaving catheterization labs, said lead investigator Yu-Chu Shen, Ph.D., an economist at the Naval Postgraduate School in Monterey, Calif.

She and her colleague found a nonsignificant trend toward increased mortality for diversion periods shorter than 12 hours, as well as "an increase of 0.2 percentage points for every hour increase in diversion. This is the first multisite, multicounty study that really quantifies the association" between diversion and acute MI mortality "on a large scale," Dr. Shen said.

The findings are based on Medicare claims data for 11,625 acute MI patients in Los Angeles, San Francisco, San Mateo, and Santa Clara counties who were treated in 2000-2005 at about 150 EDs. The researchers compared mortality outcomes when patients were able to be treated at the nearest ED vs. outcomes when their nearest ED was on diversion, typically because there were no inpatient beds available for new admissions or the catheterization lab was full.

The approximately 3%, statistically significant increase in death rates when hospitals were on 12 or more hours of diversion held true across 30- and 90-day mortality, as well as 9- and 12-month mortality.

For instance, 15% of the 3,541 patients who were able to be admitted to their nearest ED died within 30 days of their heart attack; 19% of the 2,060 whose nearest ED was on 12 or more hours of diversion died within a month, which translated to a regression-adjusted increase of 3.24% (95% confidence interval, 0.60-5.88).

Similarly, when patients’ nearest EDs were accepting new patients, 87% were admitted to a hospital with a catheterization lab; when the nearest hospital was on at least 12 hours of diversion, the number fell to 78%, Dr. Shen said (JAMA 2011;305:2440-7).

The message for physicians is to "do everything you can to keep [the ED] open," said Dr. Edward Livingston, chairman of the GI and endocrine surgery division at the University of Texas, Dallas.

"Hospitals have different thresholds for closing. Some close at the drop of a hat; others wait until they absolutely" have no choice. "Everybody [seems to have] their own criteria, but it’s really in the patient\'s best interest for hospitals to do everything possible to stay open," said Dr. Livingston, also a contributing editor at JAMA, which published the study online ahead of print to coincide with Dr. Shen’s presentation.

"We chose to publish [the study] because we think it’s an important observation. This shows a broad spectrum of hospitals in different kinds of environments with the same problem. That suggests it is a truly systemic problem, and not just a problem of one particular facility or region," which has been suggested in the past, he said.

And it’s a problem with no easy solutions, he and Dr. Shen agreed, because diversion touches on issues of resource allocation, hospital design, health care markets, competition, and other matters.

But in the short term, there "may need to be criteria that we all agree on for what makes you close. We all ought to agree that those thresholds should be really high," Dr. Livingston said.

To mitigate the adverse health outcomes associated with hospitals on diversion, "the key is increasing flow through emergency departments by moving patients who have been admitted to the hospital out of the [ED] to inpatient areas," Dr. Sandra Schneider said in a statement. A task force of emergency physicians also recommended that hospitals discharge most hospital patients before noon to make more inpatient beds available to emergency patients, and that hospitals make an effort to schedule elective and surgical cases more evenly throughout the week. Dr. Schneider is president of the American College of Emergency Physicians.

Dr. Shen said she has no disclosures. Dr. Livingston said he is a consultant for Texas Instruments. The study was funded by the Robert Wood Johnson Foundation, the National Institutes of Health, and the University of California, San Francisco.

SEATTLE – Patients having heart attacks are more likely to die if their nearest emergency department is temporarily refusing new patients, according to a study that linked heart attack outcomes to hospital diversion logs in four California counties, and that was presented at the annual research meeting of AcademyHealth.

Acute MI death rates are about 3% higher if the closest ED is on 12 or more hours of diversion on the day of the heart attack.

Treatment delays could be the reason, but patients in the study were typically accepted by another ED within a mile. Another possible explanation is that diverted patients were less likely to end up at EDs with readily available and potentially lifesaving catheterization labs, said lead investigator Yu-Chu Shen, Ph.D., an economist at the Naval Postgraduate School in Monterey, Calif.

She and her colleague found a nonsignificant trend toward increased mortality for diversion periods shorter than 12 hours, as well as "an increase of 0.2 percentage points for every hour increase in diversion. This is the first multisite, multicounty study that really quantifies the association" between diversion and acute MI mortality "on a large scale," Dr. Shen said.

The findings are based on Medicare claims data for 11,625 acute MI patients in Los Angeles, San Francisco, San Mateo, and Santa Clara counties who were treated in 2000-2005 at about 150 EDs. The researchers compared mortality outcomes when patients were able to be treated at the nearest ED vs. outcomes when their nearest ED was on diversion, typically because there were no inpatient beds available for new admissions or the catheterization lab was full.

The approximately 3%, statistically significant increase in death rates when hospitals were on 12 or more hours of diversion held true across 30- and 90-day mortality, as well as 9- and 12-month mortality.

For instance, 15% of the 3,541 patients who were able to be admitted to their nearest ED died within 30 days of their heart attack; 19% of the 2,060 whose nearest ED was on 12 or more hours of diversion died within a month, which translated to a regression-adjusted increase of 3.24% (95% confidence interval, 0.60-5.88).

Similarly, when patients’ nearest EDs were accepting new patients, 87% were admitted to a hospital with a catheterization lab; when the nearest hospital was on at least 12 hours of diversion, the number fell to 78%, Dr. Shen said (JAMA 2011;305:2440-7).

The message for physicians is to "do everything you can to keep [the ED] open," said Dr. Edward Livingston, chairman of the GI and endocrine surgery division at the University of Texas, Dallas.

"Hospitals have different thresholds for closing. Some close at the drop of a hat; others wait until they absolutely" have no choice. "Everybody [seems to have] their own criteria, but it’s really in the patient\'s best interest for hospitals to do everything possible to stay open," said Dr. Livingston, also a contributing editor at JAMA, which published the study online ahead of print to coincide with Dr. Shen’s presentation.

"We chose to publish [the study] because we think it’s an important observation. This shows a broad spectrum of hospitals in different kinds of environments with the same problem. That suggests it is a truly systemic problem, and not just a problem of one particular facility or region," which has been suggested in the past, he said.

And it’s a problem with no easy solutions, he and Dr. Shen agreed, because diversion touches on issues of resource allocation, hospital design, health care markets, competition, and other matters.

But in the short term, there "may need to be criteria that we all agree on for what makes you close. We all ought to agree that those thresholds should be really high," Dr. Livingston said.

To mitigate the adverse health outcomes associated with hospitals on diversion, "the key is increasing flow through emergency departments by moving patients who have been admitted to the hospital out of the [ED] to inpatient areas," Dr. Sandra Schneider said in a statement. A task force of emergency physicians also recommended that hospitals discharge most hospital patients before noon to make more inpatient beds available to emergency patients, and that hospitals make an effort to schedule elective and surgical cases more evenly throughout the week. Dr. Schneider is president of the American College of Emergency Physicians.

Dr. Shen said she has no disclosures. Dr. Livingston said he is a consultant for Texas Instruments. The study was funded by the Robert Wood Johnson Foundation, the National Institutes of Health, and the University of California, San Francisco.

SEATTLE – Patients having heart attacks are more likely to die if their nearest emergency department is temporarily refusing new patients, according to a study that linked heart attack outcomes to hospital diversion logs in four California counties, and that was presented at the annual research meeting of AcademyHealth.

Acute MI death rates are about 3% higher if the closest ED is on 12 or more hours of diversion on the day of the heart attack.

Treatment delays could be the reason, but patients in the study were typically accepted by another ED within a mile. Another possible explanation is that diverted patients were less likely to end up at EDs with readily available and potentially lifesaving catheterization labs, said lead investigator Yu-Chu Shen, Ph.D., an economist at the Naval Postgraduate School in Monterey, Calif.

She and her colleague found a nonsignificant trend toward increased mortality for diversion periods shorter than 12 hours, as well as "an increase of 0.2 percentage points for every hour increase in diversion. This is the first multisite, multicounty study that really quantifies the association" between diversion and acute MI mortality "on a large scale," Dr. Shen said.

The findings are based on Medicare claims data for 11,625 acute MI patients in Los Angeles, San Francisco, San Mateo, and Santa Clara counties who were treated in 2000-2005 at about 150 EDs. The researchers compared mortality outcomes when patients were able to be treated at the nearest ED vs. outcomes when their nearest ED was on diversion, typically because there were no inpatient beds available for new admissions or the catheterization lab was full.

The approximately 3%, statistically significant increase in death rates when hospitals were on 12 or more hours of diversion held true across 30- and 90-day mortality, as well as 9- and 12-month mortality.

For instance, 15% of the 3,541 patients who were able to be admitted to their nearest ED died within 30 days of their heart attack; 19% of the 2,060 whose nearest ED was on 12 or more hours of diversion died within a month, which translated to a regression-adjusted increase of 3.24% (95% confidence interval, 0.60-5.88).

Similarly, when patients’ nearest EDs were accepting new patients, 87% were admitted to a hospital with a catheterization lab; when the nearest hospital was on at least 12 hours of diversion, the number fell to 78%, Dr. Shen said (JAMA 2011;305:2440-7).

The message for physicians is to "do everything you can to keep [the ED] open," said Dr. Edward Livingston, chairman of the GI and endocrine surgery division at the University of Texas, Dallas.

"Hospitals have different thresholds for closing. Some close at the drop of a hat; others wait until they absolutely" have no choice. "Everybody [seems to have] their own criteria, but it’s really in the patient\'s best interest for hospitals to do everything possible to stay open," said Dr. Livingston, also a contributing editor at JAMA, which published the study online ahead of print to coincide with Dr. Shen’s presentation.

"We chose to publish [the study] because we think it’s an important observation. This shows a broad spectrum of hospitals in different kinds of environments with the same problem. That suggests it is a truly systemic problem, and not just a problem of one particular facility or region," which has been suggested in the past, he said.

And it’s a problem with no easy solutions, he and Dr. Shen agreed, because diversion touches on issues of resource allocation, hospital design, health care markets, competition, and other matters.

But in the short term, there "may need to be criteria that we all agree on for what makes you close. We all ought to agree that those thresholds should be really high," Dr. Livingston said.

To mitigate the adverse health outcomes associated with hospitals on diversion, "the key is increasing flow through emergency departments by moving patients who have been admitted to the hospital out of the [ED] to inpatient areas," Dr. Sandra Schneider said in a statement. A task force of emergency physicians also recommended that hospitals discharge most hospital patients before noon to make more inpatient beds available to emergency patients, and that hospitals make an effort to schedule elective and surgical cases more evenly throughout the week. Dr. Schneider is president of the American College of Emergency Physicians.

Dr. Shen said she has no disclosures. Dr. Livingston said he is a consultant for Texas Instruments. The study was funded by the Robert Wood Johnson Foundation, the National Institutes of Health, and the University of California, San Francisco.