Trends in Access to Medications for Opioid Use Disorder.

Importance: Medicaid, the largest payer for medications for opioid use disorder (MOUD), disenrolled more than 19.1 million individuals by March 2024 after the continuous coverage requirement ended in April 2023-a process termed Medicaid unwinding-but the impact on buprenorphine receipt remains unknown. Objective: To assess the association between Medicaid unwinding and dispensing of prescription buprenorphine, overall and by payment sources nationally and by state. Design, Setting, and Participants: Cross-sectional study of buprenorphine dispensing (age ≥18 years) from April 2020 to March 2024 using the IQVIA Longitudinal Prescription (LRx) database containing more than 90% of US retail pharmacy claims. Interrupted time-series estimated levels and trends of buprenorphine prescription dispensation before and after Medicaid unwinding. Main Outcomes and Measures: The number of patients with filled buprenorphine prescriptions each month was analyzed by payer type (Medicaid, Medicare, commercial, or self-pay) and by state. Stratified analyses assessed state factors, including automated (ex parte) Medicaid renewal rates (higher or lower than the median), income verification sources used for automated renewals (≤3, 4-5, or 6-7), and Affordable Care Act Medicaid expansion status. Results: Of the 2 405 970 adults who filled buprenorphine prescriptions between April 2020 and March 2024, 1 154 866 (48%) had at least 1 fill covered by Medicaid, 288 716 (12%) by Medicare, 1 106 746 (46%) by commercial insurance, and 264 657 (11%) by self-pay. Medicaid unwinding was associated with reversal of previously increasing trends in buprenorphine prescriptions, with 2.9% fewer patients (-23 855 [95% CI, -32 661 to -15 054]) receiving buprenorphine each month by 8 months after unwinding vs the month before unwinding began. This decline was driven by a 12.7% drop in patients with Medicaid-paid fills (-46 545 [95% CI, -51 362 to -41 730]), partially offset by increases in patients with commercial (6.12%, 19 809 [95% CI, 12 109 to 27 509]) and self-paid (7.24%, 2525 [95% CI, 1246 to 3805]) fills. Sixteen states saw overall declines in buprenorphine use after unwinding, with reductions among patients with Medicaid-covered prescriptions in 36 states, partially offset by increases in patients with commercial insurance covered fills (32 states) and self-paid fills (23 states). Buprenorphine prescriptions remained stable in states with above-median automated Medicaid renewal rates and more income verification sources, whereas states with below-median automated renewal rates, fewer verification sources, and nonexpansion state status experienced smaller offsets for Medicaid-related losses, highlighting importance of state-specific policies. Conclusions and Relevance: This cross-sectional study of Medicaid unwinding and filled buprenorphine prescriptions found that although shifts to commercial and self-pay sources mitigated some losses, rising self-pay reliance poses affordability barriers that threaten treatment continuity. Addressing access disparities is critical amid persistently high US overdose rates.