Medicaid Unwinding and Changes in Buprenorphine Dispensing.

Importance: After the Medicaid continuous enrollment provision ended on March 31, 2023, millions of Medicaid patients were disenrolled, a process called "Medicaid unwinding." Whether this process was associated with changes in dispensing of buprenorphine, a medication for opioid use disorder preventing opioid overdose deaths, is unknown. Objective: To evaluate changes in buprenorphine dispensing during Medicaid unwinding. Design, Setting, and Participants: This cross-sectional study used difference-in-differences analysis to assess data from the IQVIA Longitudinal Prescription Database, capturing 92% of US retail prescriptions. Treatment and comparison states were those in the top vs bottom quartile of the percentage change in adult Medicaid enrollment between the month before the state resumed Medicaid eligibility determinations and December 31, 2023. Analyses included Medicaid-insured adults with active buprenorphine prescriptions in quarter 1 from 2017 to 2023. Exposure: State-level change in adult Medicaid enrollment. The preexposure period was from July 1, 2017, to December 31, 2022, and the postexposure period was from July 1 to December 31, 2023 (quarters 3 and 4). Main Outcomes and Measures: Four outcomes assessed buprenorphine dispensing in quarters 3 and 4 from 2017 to 2023: the number of days with active buprenorphine prescriptions, no active prescriptions, 1 or more active prescriptions paid with private insurance, and 1 or more active cash-pay prescriptions. Linear and logistic regression models compared changes in outcomes over time among treatment and comparison states. Results: Analyses included 754 675 person-years from 569 069 patients (mean [SD] age, 39.2 [9.6] years; 386 719 men [51.2%]). Among adults in treatment states, the number of days with active buprenorphine prescriptions in quarters 3 and 4 decreased by 3.9 days (95% CI, -6.7 to -1.1 days) more compared with adults in comparison states. Adults in treatment states also had an increase of 1.8 percentage points (95% CI, 0.6-3.0 percentage points) in the probability of having no days with active prescriptions, an increase of 1.9 percentage points (95% CI, 0.4-3.4 percentage points) in the probability of having 1 or more active prescriptions paid with private insurance, and an increase of 0.9 percentage points (95% CI, 0.1-1.7 percentage points) in the probability of having 1 or more active cash-pay prescriptions. Conclusions and Relevance: In this cross-sectional study using difference-in-differences analysis, Medicaid patients in states with the highest vs lowest magnitude of Medicaid disenrollment through December 2023 were more likely to decrease or discontinue buprenorphine use and more likely to transition to private insurance or cash to pay for prescriptions. Findings suggest that Medicaid unwinding was associated with disruptions in buprenorphine therapy, raising concerns about the potential for increased opioid-related morbidity and mortality among patients in this population.