Major Finding: Acute MI death rates are about 3% higher if the ED closest to the patient is on 12 or more hours of diversion.
Data Source: A case-crossover study.
Disclosures: Dr. Shen said she has no disclosures. 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 acute myocardial infarctions are more likely to die if their nearest emergency department is temporarily refusing new patients, according to a study that linked acute myocardial infarction outcomes to hospital diversion logs in four California counties, and that was presented at the meeting
Acute myocardial infarction death rates are about 3% higher if the closest emergency department is on 12 or more hours of diversion on the day of the acute event.
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 emergency departments. The researchers compared mortality outcomes when patients were able to be treated at the nearest emergency department with 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 acute myocardial infarction; 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).
View on the News
Diversion Should Be Last Option
The message for physicians is to “do everything you can to keep [the ED] open,” Dr. Edward Livingston said.
“This shows a broad spectrum of hospitals in different kinds of environments with the same problem,” which suggests it is a truly systemic problem, and “not just a problem of one particular facility or region,” he said.
“Hospitals have different thresholds for closing. Some close at the drop of a hat; others wait until they absolutely” have no choice. Each hospital seems to have its own criteria, but the study shows “it's really in the patient's best interest for hospitals to do everything possible to stay open,” he added.
“We may need 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.
DR. LIVINGSTON is chairman of the GI and endocrine surgery division at the University of Texas, Dallas. He is a contributing editor at JAMA, which published the study, and a consultant for Texas Instruments.