The role of nurse practitioners in primary healthcare.

Objectives: The employment of more nurse practitioners (NPs) is one of the most promising ways to expand the capacity of medical group practices. The objective of this study was to determine the association of NPs with patient-level cost and quality of care.

Study Design: Eighty-five primary care medical group practices were matched with 315,000 Medicare patients. Per beneficiary per year total costs and quality of care were calculated from Medicare claims data. Data were analyzed using multivariate regression analysis.

Methods: A national sample of primary care medical group practices based on responses to the 2009 Medical Group Management Association Performance Survey. The cost variable was annual risk-adjusted Medicare expenditures per capita for patients attributed to a practice. There were 5 quality of care measures.

Results: Employing NPs in primary care practices is associated with increased risk-adjusted patient cost for up to 1 NP for every 2 physicians, but cost decreases as the number of NPs per physician increases. There was little evidence of systematic association of NPs with quality of care or the practice's net revenue.

Conclusions: Primary care medical group practices need to evaluate the alternate clinical roles of their NPs and develop models that optimize cost and quality of care. Practices that have employed more than 1 NP for every 2 physicians appear to have lower per capita Medicare spending with no adverse effects on quality. Research now needs to explore these causalities.