Ambulatory Care Visits to Physician Offices, Hospital Outpatient Departments, and Emergency Departments: United States, 1999-2000

For Release: Thursday, September 23, 2004

Contact: NCHS/CDC Public Affairs, (301) 458-4800


Ambulatory Care Visits to Physician Offices, Hospital Outpatient Departments, and Emergency Departments: United States , 1999-2000. Series Report 13, No. 157. 78 pp. (PHS) 2004-1728. pdf icon[PDF – 4.3 MB]

This new report by CDC showcases the use of ambulatory medical care services across a broad range of health care settings and paints a picture of variation in medical services obtained by safety-net populations, including African Americans, poor, uninsured, and persons living in sparsely-populated areas of the country. The report also documents how use of emergency departments varies from less-critical health care settings among differing populations. Some of the findings include:

  • Emergency departments provide one-quarter of care received by uninsured patients compared with one-tenth by privately-insured patients. For every visit to the emergency department by an uninsured patient, there are 1.3 visits to a primary care specialist compared with 6.6 primary care visits for every emergency department visit by a privately-insured patient.
  • Uninsured patients are much less likely than privately-insured patients to have medication prescribed during their visits. Meanwhile, more medications are prescribed at visits in sparsely-populated areas compared with densely-populated areas.
  • Compared with densely-populated areas, patients seeking care in sparsely-populated areas are more likely to visit primary care specialists such as family practice or internal medicine specialists but less likely to visit medical specialists such as dermatologists, psychiatrists, and allergy specialists. In addition, use of ambulance transports to emergency departments is more than twice the rate in sparsely-populated areas compared with densely-populated areas (118 vs. 53 transports per 1,000 persons).
  • Age-adjusted visit rates showed that between 1993-94 and 1999-2000, use of primary care specialists and surgical care specialists increased while use of medical care specialists decreased. Use of hospital settings did not change. This coincides with an increase in use of HMOs and managed care plans during the study period.
  • Out of the nearly one billion annual ambulatory medical care visits across all settings, nearly one-half were to primary care specialty offices, 16-17 percent each to surgical and medical specialty offices, 11 percent to hospital emergency departments, and 9 percent to hospital outpatient departments with physician-supervised evaluation and management clinics.
  • There were 375,000 medical visits for injuries, poisonings, and adverse effects of medical treatment, representing 14 percent of all ambulatory care visits. The leading illness-related diagnoses included high blood pressure, common cold, arthropathies, and diabetes. Drugs were prescribed at 67 percent of visits with the top therapeutic classes including antiarthritics, antidepressants, and vaccines.

The report is based on combined data from the 1999 and 2000 National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey, which are annual probability-based surveys of ambulatory care utilization in the United States conducted by CDC’s National Center for Health Statistics. The five health care settings studied include primary care offices, surgical specialty offices, medical specialty offices, hospital outpatient departments, and emergency departments.


Page last reviewed: October 6, 2006