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Study profiles the number, distribution, and basic use patterns of U.S. emergency departments

Of the 4,917 hospitals in the United States, 4,862 have an emergency department (ED). The distribution and use of these EDs varies dramatically, according to a 2001 profile study. For example, a median of 15,711 patients visited U.S. EDs in 2001. However, 1 in 3 U.S. EDs saw less than 8,760 patients and, together, accounted for only 6 percent of all ED visits. This volume of patients is equal to an average of at least one patient per hour, 24 hours per day, 7 days per week. Excluding the low-volume EDs, the remaining two-thirds of EDs typically saw 28,000 patients per year and accounted for 94 percent of all ED visits. The highest volume hospitals saw a median of 48,920 patients per year.

State-specific ED visit rates ranged from a low of 23 visits per year per 100 people in Hawaii to 65 visits per 100 people in Washington, DC. ED visit rates were highest in Washington, DC, West Virginia, and Mississippi. Most (83 percent) of the small-volume EDs were concentrated in rural areas, with only 17 percent located in metropolitan areas. In contrast, only 28 percent of high-volume EDs were in a nonurban setting, with 72 percent located in metropolitan areas.

The proportion of higher volume EDs also varied by region. In 2001, 72 percent of the 1,834 EDs in the South were considered higher volume (more than 8,760 patients per year). The Midwest had a total of 1,425 EDs, 55 percent of which were higher volume. The West had a total of 890 EDs of which 66 percent were higher volume.

The Northeast had the lowest number of EDs (713), but the highest percentage of higher volume EDs (89 percent). The Northeast received the most annual visits per ED and the Midwest received the fewest. Regional ED use can be influenced by heavy "safety net" use by persons without a usual care provider, primary care shortages in the area, and patients' proximity to an ED.

The profiles were based on data from the first national database of U.S. EDs, the National Emergency Department Inventory, which was developed by the study authors. They suggest that the United States should consider classifying EDs as it does trauma centers. The study was supported in part by the Agency for Healthcare Research and Quality (HS13099).

See "A profile of U.S. emergency departments in 2001," by Ashley F. Sullivan, M.S., M.P.H., Ilana B. Richman, B.A., Christina J. Ahn, B.A., and others, in the December 2006 Annals of Emergency Medicine 48(6), pp. 694-701.

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