BACKGROUND AND AIMS: Maintenance on medications for opioid use disorder, particularly buprenorphine, is critical for reducing overdose risk and improving health outcomes in the United States. This study evaluates retention and dropout probabilities between sublingual buprenorphine (SL-BUP) and extended-release buprenorphine (XR-BUP) among commercially-insured individuals with opioid use disorder (OUD). DESIGN AND SETTING: A retrospective cohort study using Meretive™ Markeskan® claims data from 2019 to 2020. A multi-state Markov model assessed transitions between treatment states over 12 months. PARTICIPANTS: The study included 58,933 individuals aged 18-64 years with OUD, initiating SL-BUP (n = 57,520) or XR-BUP (n = 1,413). XR-BUP patients were divided into XR-BUP only (n = 684
49 %) and XR-BUP with supplemental SL-BUP (XR-BUP+sSL
n = 729
51 %). MEASUREMENTS: Primary outcomes included probabilities of remaining in treatment or transitioning between states at 1, 3, 6, and 12 months. The impact of dosage and days of supply on retention was also examined. RESULTS: The probability of permanent treatment dropout at 6 months was similar for SL-BUP (38.59 %, 95 % CI: 37.9 %-39.4 %) and XR-BUP (41.3 % 95 %CI: 36.8 %-46.1 %), yet the probability of remaining in treatment was significantly higher for SL-BUP than XR-BUP (49.5 %
95 %CI: 48.8 %-50.1 % vs. 13.5 % 95 % CI: 10.5 %-16.5 %). The high proportion of individuals initially prescribed XR-BUP later transitioned to SL-BUP. Higher doses and longer days supplied of SL-BUP reduced dropout rates. Among patients receiving ≥16 mg/day and ≥28 days, dropout probabilities were 5.7 % (95 % CI: 5.4 %-6.0 %) at 1 month, 15.4 % (95 % CI: 14.8 %-16.2 %) at 3 months, 28.0 % (95 % CI: 26.9 %-29.2 %) at 6 months, and 47.8 % (95 %CI: 45.2 %-49.5 %) at 12 months. In contrast, patients prescribed <
16 mg/day and <
28 days had a 46.3 % (95 %CI: 45.0 %-47.6 %) dropout rate by 6 months. CONCLUSION: SL-BUP demonstrates higher retention rates and lower dropout compared to XR-BUP in real-world settings. Optimizing SL-BUP dosing and providing extended supplies can improve retention and reduce treatment discontinuation.