Geographical Variation in the Supply of Nurse Practitioners in United States

Nurse Practitioners (NPs) are an important component of healthcare workforce in the United States. Prior research have shown that NPs provide high-quality and cost-effective patient care in a variety of healthcare settings. Current shortage of physicians will create an increased demand for non-clinician workforce, such as NPs and physician assistants (PAs). The objective of the study is to analyze the distribution of NPs in the US. We used the 2010 Area Resource File Data to identify NPs with an individual National Provider Identification (NPI) number. For all the US counties having at least one NP, we used logistic regression to identify factors associated with the supply of NPs. Independent variables were grouped as health services, legal environment, and rurality. At health services level, counties with higher number of primary care physicians/100,000 population are more likely to have an NP, while counties with higher number of PAs/100,000 population are less likely to have an NP. Number of hospital beds and overall physician growth were not related to presence of an NP. The odds of having an NP are higher for the counties where state laws allow NPs to practice independently without physician supervision. Rurality did not affect the likelihood of having an NP. Adequate supply of primary care physicians is important for supply of nurse practitioners at county level. Lack of uniformity in scope of practice between the states may create supply/demand issues as NP will be more likely to practice in those states that have a favorable legal environment.