Buprenorphine Dispensing Following Medicaid Expansion Amid Unwinding in North Carolina.

Importance: The continuous Medicaid enrollment provision adopted during the COVID-19 pandemic ended in March 2023, after which 24 million US residents were disenrolled. Prior studies suggest this "unwinding" was associated with increased discontinuation of buprenorphine, an effective treatment for opioid use disorder. On December 1, 2023, North Carolina expanded Medicaid to low-income adults under the Patient Protection and Affordable Care Act (ACA). Objective: To evaluate changes in buprenorphine dispensing following North Carolina's Medicaid expansion. Design, Setting, and Participants: This cross-sectional study used a difference-in-differences analysis of the IQVIA Longitudinal Prescription Database, which captures 92% of US prescriptions. The analysis was limited to North Carolina and South Carolina, which has not expanded Medicaid under the ACA. The sample included adults with Medicaid-paid buprenorphine prescriptions from March to May 2023, 3 months before unwinding began in these states. The preintervention period was June 1 to November 30, 2023, and the postintervention period was December 1, 2023 to December 31, 2024. Exposure: North Carolina's Medicaid expansion. Main Outcomes and Measures: Monthly proportion of patients with at least 1 active buprenorphine prescription; monthly proportion of patients with at least 1 active prescription paid by Medicaid, private insurance, or cash. Linear probability models estimated differential changes in outcomes over time in North Carolina vs South Carolina. Results: Analyses included 286 216 person-months of data from 15 064 patients (mean [SD] age, 39.8 [9.2] years; 210 881 person-months [73.7%] contributed by women). The monthly proportion of patients with at least 1 active buprenorphine prescription declined by 11.3 and 11.2 percentage points in North Carolina and South Carolina, respectively, between June and November 2023. North Carolina's Medicaid expansion was associated with a 1.6 (95% CI, 0.9-2.3) percentage point differential increase in this proportion, a 7.4 (95% CI, 5.7-9.1) percentage point differential increase in the probability of having at least 1 Medicaid-paid prescription, a -4.1 (95% CI, -5.2 to -3.0) percentage point differential change in the probability of having at least 1 private-pay prescription, and a -1.4 (95% CI, -2.6 to -0.3) percentage point differential change in the probability of having at least 1 cash-pay prescription. Conclusions and Relevance: In this cross-sectional study of prescription dispensing data, North Carolina's Medicaid expansion was associated with a slowing of the decline in buprenorphine dispensing that occurred after unwinding of Medicaid continuous coverage requirement began. Medicaid expansion may have partially mitigated the adverse changes in buprenorphine dispensing associated with unwinding.