Overuse and inappropriate use of emergency departments (EDs) remains an important issue in health policy. After implementation of Medicaid expansion, many states experienced an increase in ED use, but the magnitude varied. Differential access to primary care might explain such variation.
To determine whether the increase in ED use among Medicaid enrollees following Medicaid expansion was smaller in states that allowed greater access to primary care providers by permitting nurse practitioners (NPs) to practice without physician oversight.
Examining data on ED use by Medicaid beneficiaries, we estimated random effects models to examine changes in ED visits. Models for 8 different clinical conditions were estimated, with each model including a linear time trend, indicators for Medicaid expansion and for the absence of physician oversight requirements, and an interaction between these 2 indicators.
States requiring physician oversight of NPs had a 28% increase in ED visits relative to the preexpansion period, while states allowing NP practice without physician oversight had only a 7% increase. The increase in the share of visits covered by Medicaid in no-oversight states was 40% of the size of the increase in oversight states.
Allowing NPs to practice without physician oversight was associated with a reduction in the magnitude of increase in ED use following Medicaid expansion. States that restrict NP practice should weigh the costs of maintaining these restrictions against the potential benefits of lower ED use. States considering Medicaid expansion should also consider relaxing NP scope-of-practice laws.