Black patients more likely to suffer with ER ambulance diversion

African American patients suffering heart conditions are more likely than white patients to have their ambulance diverted to another hospital due to overcrowding in their nearest emergency room, according to a new UC San Francisco study.

Furthermore, when the nearest hospital had significant ambulance diversion, black patients had a lower chance of receiving specialized cardiac care and lower one-year survival rates, in keeping with what was previously known about ambulance diversion and its association with worse long-term mortality.

The study will appear March 17 in BMJ Open.

"The take-home findings from this study are two-fold," said Renee Hsia, MD, professor of emergency medicine and health policy at UCSF. "First, we now better understand the mechanisms behind emergency department crowding and how it affects patients. Not only are crowded hospitals less able to deliver high-quality care, but even sick patients get diverted to hospitals with less technology. On top of that, they are less likely to receive appropriate treatment.

"Secondly, we have definitive evidence that minority-serving hospitals, or hospitals that serve a high proportion of black patients, tend to experience higher levels of emergency department crowding," Hsia said.

The study, which linked daily ambulance diversion logs from 26 California counties to Medicare patient records with acute myocardial infarction, or heart attacks, between 2001 and 2011, investigated the differences in access, treatment and outcomes between black and white patients at different stages of ambulance diversion.

The sample included nearly 30,000 patients: half experienced no diversion, 25 percent experienced six hours or less of diversion, 15 percent had 6-12 hours of diversion, and 10 percent had more than 12 hours of diversion.

Patients in minority-serving hospitals – particularly those serving a large share of black patients – were more likely to be on diversion, said the authors.

Specifically, patients exposed to more than 12 hours of diversion had a 4.4 percent reduction in access to cardiac care units, and a 3.4 percent reduction in access to catheterization labs or facilities specializing in procedures to improve blood flow to the heart.

Additionally, patients faced with the highest level of ambulance diversion had a lower chance of receiving catheterization (4.3 percent) and higher one-year mortality (9.6 percent).

"Our hope is that we can take this evidence and translate it into change at the systems level," Hsia said. "While focusing efforts to decrease emergency department crowding is necessary in all hospitals, it might be more 'bang for the buck' if we want to make a dent in decreasing disparities by targeting efforts in minority-serving hospitals."