National Hospital Ambulatory Medical Care Survey: 2004 outpatient department summary.

Objectives: This report describes ambulatory care visits to hospital OPDs in the United States. Statistics are presented on selected hospital, patient, and visit characteristics. Selected trends in OPD utilization from 1994 through 2004 are also presented.

Methods: The data presented in this report were collected in the 2004 NHAMCS, a national probability sample survey of visits to emergency and outpatient departments of nonfederal, short-stay, and general hospitals in the United States. Selected comparisons are also made with data from the 2004 National Ambulatory Medical Care Survey (NAMCS), a national probability sample survey of visits to office-based physicians in the United States. Sample data are weighted to produce annual national estimates.

Results: During 2004, an estimated 85.0 million visits were made to hospital OPDs in the United States, about 29.5 visits per 100 persons. Females (35.1 per 100 persons) had higher OPD visit rates than males (23.6 per 100 persons), and black or African American persons (50.3 per 100 persons) had higher OPD visit rates than white persons (27.0 visits per 100 persons). The overwhelming majority of visits to hospital OPDs were made by established patients (85.4 percent). Females made 75.5 percent of preventive care visits. The preventive care visit rate by Hispanic or Latino patients was twice the rate of non-Hispanic patients. Diagnostic and screening services were ordered at 90.3 percent of visits, therapeutic and preventive services were ordered at 50.0 percent of visits, and medications were ordered at 67.4 percent of visits. The proportion of visits involving only midlevel providers increased from 5.9 in 1993-94 to 11.4 percent of visits in 2003-04.