Community-level factors influencing the duration of buprenorphine treatment in individuals with opioid use disorder: a cohort study using US longitudinal claims data.

Introduction: Buprenorphine is effective in reducing opioid-related morbidity and mortality; however, many patients discontinue treatment prematurely. While previous research has focused on individual-level predictors of retention, the influence of community context remains underexplored. This study aims to examine how community-level factors, such as social vulnerability, availability of buprenorphine-waivered providers and access to behavioural health services, affect the duration of buprenorphine treatment episodes for individuals with opioid use disorder (OUD). Methods: We conducted a retrospective cohort study using longitudinal claims data from 2006 to 2022. Adults aged 18 and older who initiated buprenorphine treatment for OUD and maintained continuous enrolment were included. Treatment episodes were defined by refill continuity, monitored until a gap of greater than 14 days occurred. Patient ZIP codes were linked to Social Vulnerability Index scores, provider density and behavioural health facility availability. The primary outcome was treatment duration, classified into short-term (0-3 months), medium-term (3-6 months), extended medium-term (6-12 months) and long-term (>12 months). Associations were identified using stepwise multinomial logistic regression. Results: From the 131 169 individuals (303 528 buprenorphine treatment episodes), most of them were males (60.8%), aged 18-34 years (47.7%), and commercially insured (76.0%). For medium-term duration, individuals living in low-vulnerable areas (OR: 1.14 (1.36-1.47)), with high provider density (1.07 (1.02-1.12)) and high mental health service availability (1.20 (1.15-1.25)) were associated with longer retention. Effect size increased for extended medium-term durations, including low vulnerability (1.73 (1.67-1.80)) and high mental health service availability (1.31 (1.26-1.37)). In long-term treatment episodes, those living in low-vulnerable areas (1.95 (1.89-2.02)), high provider density (1.1 (1.06-1.15)) and high mental health services access (1.58 (1.52-1.64)) presented an increased effect size in the odds. Conclusions: Social vulnerability, provider availability and mental health service access are significantly associated with buprenorphine treatment duration. Addressing these access inequities could improve retention for individuals with OUD.