Researchers say race factors into determining where ambulances take patients, but it's unclear whether biases drive the disparity.
In first-of-its-kind research, a new study examining emergency medical service transportation patterns found black and Hispanic patients were less likely to be transported to ERs most frequented by white patients living in the same ZIP code; that's despite it often being the closest facility, which is what national guidelines suggest.
But the study, published Friday in JAMA Network Open, found black and Hispanic patients more often were taken to safety-net hospital emergency departments than white patients living in the same ZIP code.
The analysis used national Medicare claims data on nearly 865,000 patients age 66 and older from more than 4,100 ZIP codes who had about 460,000 ED visits using EMS transport from 2006 to 2012.
White patients were transported to the emergency department destination they most frequently visited more than 61% of the time while EMS transported black patients to the same destination 5.3% less often and 2.5% less often for Hispanic patients.
White patients visited safety-net hospital 18% of the time while black patients visited those settings 2.7% more often and Hispanics 1.9% more often. The largest disparities were found in urban areas with multiple ED destinations.
The study is the first to examine ambulance transport patterns at the population level.
Study co-authors Amresh Hanchate, an associate professor of medicine at Boston University School of Medicine, and Dr. James Feldman, vice chair of research for the emergency medicine department at Boston Medical Center, say research into patients who drive themselves to the ER showed similar patterns.
"To some extent (it) may reflect patient preferences," Hanchate said. "We found quite a bit of overlap when patients went on their own."
Feldman said more research was needed to determine whether the differences in ED destinations contributed to poorer outcomes among those transported to facilities that were farther away compared to closer EDs.
"This is a first step in research that will prompt other investigations that will look critically at the interplay between patient choice, disease severity and acuity, hospital capability and whether there are other factors that are guiding transportation decision," Feldman said.
EMS providers can determine whether to take a patient based on a number of factors: their own training and ability to care for the patient based on their condition; the time of day the emergency is occurring; and whether a particular ED has reached it capacity, said Sharon Holman, president of the Sinai Urban Health Institute, a research arm that works on addressing health disparities for Chicago-based safety-net provider, Sinai Health system.
Holman said the difference can depend on what part of a neighborhood a patient resides in.
"In Chicago our ZIP code areas are pretty big," Holman said. "Sometimes where you're at in the ZIP code puts you closer to Sinai versus Rush" University Medical Center.