Scope-of-Practice Laws and Patient Safety: Evidence from the Opioid Crisis

The increased use of nurse practitioners (NPs) to alleviate healthcare provider shortages and increase access to healthcare has gained traction as a viable policy option over the last two decades. However, restrictive scope-of-practice laws that inhibit NPs’ ability to accomplish these goals remain in place, justified as necessary to protect patients from providers with less training than physicians. In this study, I examine the validity of this justification by analyzing whether allowing NPs to practice independently undermines patient safety. To do so, I focus on the ongoing opioid crisis, which has substantial implications for patient safety.

Specifically, I analyze a dataset of over 1.3 billion opioid prescriptions aggregated to the individual provider level. Based on the prescription-level information, I calculate the morphine milligram equivalent (MME) for each individual prescription as well as the total days supply of each prescription. I then aggregate this information to the individual provider-year level and examine the effect of allowing NPs to practice independently on these highly specific measures of opioid prescribing. I also analyze whether allowing independent practice affects the number of patients receiving opioids from a given provider.

Across all three measures of opioid prescribing, I find that relaxing scope-of-practice laws to grant NPs more authority results in a decrease in the overall amount of opioids prescribed. More specifically, NPs prescribe more opioids and physicians prescribe fewer opioids, with the decrease in physician prescriptions generally outweighing the increase in NP prescriptions. For example, allowing NPs to practice independently results in a 1.2 percent decrease in the annual MMEs prescribed across all providers. NPs increase the amount of MMEs they prescribe by 6.1 percent, and physicians decrease the MMEs they prescribe by 2.5 percent. Because physicians outnumber NPs and because physicians prescribe, on average, more MMEs, the relatively smaller decrease in physician prescriptions and relatively larger increase in NP prescriptions have a net negative effect on the amount of MMEs prescribed across all providers.

The results of this study suggest that, contrary to the stated reason for maintaining restrictive NP scope-of-practice laws, allowing NPs to practice independently does not result in decreased patient safety—at least in the context of dangerous prescription drugs. This evidence has important implications for the ongoing debate over scope-of-practice laws and provides support for the National Academy of Medicine’s conclusion that NPs should be allowed to practice to the full extent of their training. Additionally, while scope-of-practice laws are not generally mentioned in the debate over the opioid crisis, the results here suggest that changing how the healthcare workforce is regulated via scope-of-practice laws could play a role in mitigating the effects of this crisis.