A profile of freestanding emergency departments in the United States, 2007.

BACKGROUND: Freestanding Emergency Departments (FSEDs) have emerged as an alternative to traditional hospital-based emergency care.

STUDY OBJECTIVE: We sought to determine the number, basic types, distribution, and characteristics of United States (US) FSEDs in 2007.

METHODS: Combining data from the 2007 National Emergency Department Inventory-USA database, the 2007 American Hospital Association Annual Survey of Hospitals, Internet searches, and telephone calls, we established an inventory of FSEDs. We define FSEDs as emergency care facilities physically distinct from a hospital. FSEDs include "satellite" Emergency Departments (EDs), which are owned by a parent hospital, and "autonomous" EDs, which lack such an affiliation.

RESULTS: We identified 80 FSEDs operating in 2007, representing 1.6% of all US EDs; 73 (91%) in 20 states were satellite EDs, and seven (9%) in three states were autonomous EDs. Most FSEDs (92%; 95% confidence interval 83-97%) were located in urban areas, which is considerably higher than the proportion for hospital-based EDs (58%). The median distance from a satellite ED to a parent hospital ED was 10.6 miles. In 2007, FSED annual visit volumes ranged from 700 to 56,545 visits. The 2007 median visit volume was 18,769 (interquartile range 11,106-23,504; n = 52). This value did not vary by geographic region and is almost identical to the 2007 median visit volume for hospital-based EDs (18,776 visits).

CONCLUSIONS: FSEDs represent <2% of US EDs, with satellite EDs comprising a majority of all FSEDs. Most (92%) FSEDs are located in urban areas.