Context The US primary care safety net is composed of a loose network of community
health centers, hospital outpatient departments, and physicians' offices.
National data on how the mix of patients and services differ across sites
Objective To develop and contrast national profiles of patient and service mix
for primary care.
Design, Setting, and Patients Comparative analyses of 3 national surveys of primary care visits occurring
in 1994: for data on physician's office visits, the National Ambulatory Medical
Care Survey (NAMCS); for hospital outpatient department data, the National
Hospital Ambulatory Medical Care Survery (NHAMCS); and for data on community
health centers, the Bureau of Primary Health Care's 1994 Survey of Visits
to Community Health Centers. A time trend analysis also was conducted using
the 1998 NAMCS and NHAMCS.
Main Outcome Measures National estimates of primary care visit rates, types of patient presentation,
patient case-mix, disposition of patients, and management interventions in
1994, and compared with 1998 data.
Results The US population made 1.3 primary care visits per person in 1994, which
accounted for 43.5% of all ambulatory visits to physicians' offices, community
health centers, and hospital outpatient departments. Primary care visits per
person were 20% lower for Hispanics and 33% lower for black, non-Hispanic
persons compared with white, non-Hispanic persons. Visits to community health
centers were more likely to be made by ethnic minorities, patients with Medicaid
or no insurance, and rural dwellers than visits made to the other delivery
sites. Visits at hospital outpatient departments were made by sicker populations
and were characterized by less continuity than the other delivery sites. Controlling
for patient mix, visits made to hospital outpatient departments were more
commonly associated with imaging studies, minor surgery, and specialty referrals
than those made to physicians' offices. In 1998, the US population made an
estimated 3.4 visits per person, 45.6% of which were primary care visits.
National estimates of primary care visit rates and patient mix and practice
pattern comparisons between hospital outpatient departments and physicians'
offices were similar in 1998 and 1994.
Conclusions Expanding community health centers will likely improve access to primary
care for vulnerable US populations. However, enhancing access to of physicians'
offices is also needed to bolster the safety net. The greater service intensity
and poorer continuity for primary care visits in hospital outpatient departments
that we observed raises concern about the suitability of these clinics as
primary care delivery sites.