Nurse Practitioners and their Effects on Visits to Primary Care Providers

Shortages of primary care physicians (PCPs) has been a growing public health concern in the U.S. Current health workforce projections indicate that the shortage of PCPs is likely to worsen, and by 2025 the country will require 52,000 additional PCPs. Some possible explanations for the projected mismatch of PCPs vis-à-vis expected increases in demand for primary health care services are population growth, disproportionate aging of the population, and the passage of the 2010 Affordable Care Act - which is expected to extend health insurance coverage to an estimated 34 million people in the U.S.

Expanding the use of other health care professionals, such as nurse practitioners (NPs) and physician assistants (PAs) is among a number of proposals put forward to help alleviate the current PCP shortage. However, the extent to which NPs can fill the void for PCPs in the current market structure remain mostly unknown in the literature.

This study uses recent data from the Medical Expenditures Panel Survey (MEPS) on 25-64 years old adults to identify the effect of a NP visit on the probability of visiting a PCP, the number of visits to a PCP, and specific services provided by PCPs such as medication prescribing, general check-ups, diagnosis, and vaccinations. We control for endogeneity associated with non-random selection into NP visits using a system of simultaneous equations where states’ education requirements for obtaining a NP license serves as an identifying exclusion.

Our results indicate significant negative effects of patients’ visits to a NP on visits to a PCP with an elasticity of 0.07%. We conducted several robustness checks. First, the model passed a falsification test:  the effects of a NP visit were not significantly associated with visits to a dentist, an optometrist, and a psychologist. Second, in a dynamic specification, our findings were qualitatively similar to results from the initial specifications. In particular, patients’ visits to a NP in the previous period decrease the probability of a PCP visit in the current period. These results suggest that the care provided by the two professions has significant overlap and NPs could serve as a potential option for filling the shortage in the supply of primary care services.