National Ambulatory Medical Care Survey: 2004 summary.

Objectives: This report describes ambulatory care visits made to physician offices in the United States. Statistics are presented on selected characteristics of the physician's practice, the patient, and the visit. Selected trends in office visits are also presented.

Methods: The data presented in this report were collected in 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 using an estimator that uses a revised nonresponse adjustment.

Results: During 2004, an estimated 910.9 million visits were made to physician offices in the United States, an overall rate of 315.9 visits per 100 persons. Overall, 58.9 percent of visits were to physicians in the specialties of general and family practice, internal medicine, pediatrics, and obstetrics and gynecology. In 2004, primary care specialists provided 87.2 percent of all preventive care visits. The percentage of visits relying on Medicaid or the State Children's Health Insurance Program increased by 36% between 2001 and 2004. Essential hypertension, malignant neoplasms, acute upper respiratory infection, and diabetes mellitus were the leading illness-related primary diagnoses. There were an estimated 105.3 million injury-related visits in 2004, or 36.5 visits per 100 persons. Diagnostic or screening services were ordered or provided at 85.9 percent of visits, and counseling, education, therapeutic, or preventative services were ordered or provided at 42.0 percent of visits. Medications were prescribed or provided at 64.2 percent of visits.