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  • Publication # 13-RA006

Hospitals serving large minority populations have higher ambulance diversion rates

Disparities/Minority Health

When emergency departments (EDs) become overcrowded, the hospital may divert ambulances to other institutions. Such diversions increase the time to care, which can have adverse outcomes for heart attack patients and others. Hospitals serving a predominantly minority population are more likely to divert ambulances than institutions that treat a lower proportion of minorities, reveals a new study. The researchers examined ambulance diversion for 202 hospitals in California during 2007. EDs offering either basic or comprehensive services were included in the study. The researchers calculated hospital minority populations and the annual number of diversion hours for each hospital.

The mean number of hours on diversion for these hospitals was 724 per year. Substantial variation in annual diversion hours was observed within each county and among different counties. Hospitals serving large minority populations were at the greatest risk for experiencing ambulance diversion. Those hospitals at the 90th percentile of minority ED visitors had 306 hours of annual ambulance diversion. This was 4.1 times that of hospitals who served a 10th percentile of minority visitors. These hospitals had only 75 hours of diversion. Even when the researchers controlled for such things as ED capacity, hospital ownership, and other factors, minority-serving hospitals were still more likely to divert ambulances to another hospital ED. Since diversion is a symptom of ED crowding issues, the researchers propose that diversion bans be put into place. This has already been done in Massachusetts, where there has been no significant increase in wait times due to the ban. Putting a ban into place, either regionally or statewide, would force hospitals to examine other contributors to ED crowding, such as inadequate management of patient flow. The study was supported in part by the Agency for Healthcare Research and Quality (HS18098).

See "California hospitals serving large minority populations were more likely than others to employ ambulance diversion," by Renee Yuen-Jan Hsia, M.D., Steven M. Asch, M.D., M.P.H., Robert E. Weiss, Ph.D., and others in the August 2012 Health Affairs 31(8), pp. 1767-1776.


Page last reviewed March 2013
Internet Citation: Hospitals serving large minority populations have higher ambulance diversion rates: Disparities/Minority Health. March 2013. Agency for Healthcare Research and Quality, Rockville, MD.


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