Health care utilization and the proportion of primary care physicians.

BACKGROUND: The impact of primary care physicians on health care utilization remains controversial. Some have hypothesized that primary care physicians decrease health care utilization through enhanced coordination of care and a preventive care focus.
METHODS: Using data from the Area Resource File (a Health Resources and Services Administration US county-level database) for the years 1990, 1995, and 1999, we performed a retrospective cross-sectional analysis with generalized estimating equations to determine if measures of health care utilization (inpatient admissions, outpatient visits, emergency department visits, and surgeries) were associated with the proportion of primary care physicians to total physicians within metropolitan statistical areas.
RESULTS: The average proportion of primary care physicians in each metropolitan statistical area was 0.34 (SD 0.46, range 0.20-0.54). Higher proportions of primary care physicians were associated with significantly decreased utilization, with each 1% increase in proportion of primary care physicians associated with decreased yearly utilization for an average-sized metropolitan statistical area of 503 admissions, 2968 emergency department visits, and 512 surgeries (all P <.03). These relationships were consistent each year studied.
CONCLUSIONS: Increased proportions of primary care physicians appear to be associated with significant decreases in measures of health care utilization across the 1990s. National efforts aimed at limiting health care utilization may benefit from focusing on the proportion of primary care physicians relative to specialists in this country.