The Contribution of Nurse Practitioners and Physician Assistants to Generalist Care in Washington State

OBJECTIVE: To quantify the total contribution to generalist care made by nurse practitioners (NPs) and physician assistants (PAs) in Washington State. DATA SOURCES: State professional licensure renewal survey data from 1998-1999. STUDY DESIGN: Cross-sectional. Data on medical specialty, place of practice, and outpatient visits performed were used to estimate productivity of generalist physicians, NPs, and PAs. Provider head counts were adjusted for missing specialty and productivity data and converted into family physician full-time equivalents (FTEs) to facilitate estimation of total contribution to generalist care made by each provider type. PRINCIPAL FINDINGS: Nurse practitioners and physician assistants make up 23.4 percent of the generalist provider population and provide 21.0 percent of the generalist outpatient visits in Washington State. The NP/PA contribution to generalist care is higher in rural areas (24.7 percent of total visits compared to 20.1 percent in urban areas). The PAs and NPs provide 50.3 percent of generalist visits provided by women in rural areas, 36.5 percent in urban areas. When productivity data were converted into family physician FTEs, the productivity adjustments were large. A total of 4,189 generalist physicians produced only 2,760 family physician FTEs (1 FTE = 105 outpatient visits per week). The NP and PA productivity adjustments were also quite large. CONCLUSIONS: Accurate estimates of available generalist care must take into account the contributions of NPs and PAs. Additionally, simple head counts of licensed providers are likely to result in substantial overestimates of available care. Actual productivity data or empirically derived adjustment factors must be used for accurate estimation of provider shortages.