Homeless patients' use of urban emergency departments in the United States.

Data from the 2009-2010 National Hospital Ambulatory Care Survey-Emergency Department were used to compare homeless patients' utilization of the urban emergency department (ED) in the United States with nonhomeless patients and to examine the relationship between homelessness and demographics and ED utilization measures. The weighted sample size was 200 645 347. A total of 1 302 256 patients (0.65%) were homeless. Homeless patients were significantly more likely to be older, male, have self-pay, have no charge/charity or other as payment type, arrive via ambulance, have a longer ED visit, and a past visit to the same ED in the last year.