Nurse Practitioner Scope-of-Practice Laws and Opioid Prescribing

Context: As many parts of the United States continue to face physician shortages, the increased use of nurse practitioners (NPs) can improve access to care. However, state scope-of-practice (SOP) laws limit the ability of NPs to provide care by restricting the services they can provide and often requiring physician supervision of their practices. One important justification for the continuation of these restrictive SOP laws is preventing the overprescription of certain medications, particularly opioids.

Methods: This study examined a data set of approximately 1.5 billion individual opioid prescriptions between 2011 and 2018, which were aggregated to the individual provider-year level. A series of difference-in-differences regression models was estimated to examine the association between laws allowing NPs to practice independently and opioid prescribing patterns among physicians and NPs. Opioid prescriptions were measured in total annual morphine milligram equivalents (MMEs) prescribed by individual providers.

Findings: Across all NPs and physicians, independent NP practice was associated with a statistically significant decline of 6%, 2%, 3%, 7%, and 5% in total annual MMEs prescribed to commercially insured, cash-paying, Medicare, government-assistance, and all patients, respectively. Medicaid patients saw no statistically significant change in annual MMEs. Across all payers, NPs generally increase and physicians generally decrease the number of opioids they prescribe following a grant of NP independence. These counterbalancing changes result in an overall net decline in MMEs.

Conclusions: No evidence supports the contention that allowing NPs to practice independently increases opioid prescriptions. The results support policy changes that allow NPs to practice independently.

Keywords: nurse practitioner, scope of practice, opioids.

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