Do out-of-pocket costs influence retention and adherence to medications for opioid use disorder?

Background: Availability of medications for opioid use disorder (MOUD) has increased during the past two decades but treatment retention and adherence remain low. This study aimed to measure the impact of out-ofpocket buprenorphine cost on treatment retention and adherence among US commercially insured patients. Methods: Medical payment records from IBM MarketScan were analyzed for 6,439 adults age 18-64 years with commercial insurance who initiated buprenorphine treatment during January 1, 2016 to June 30, 2017. Regression models analyzed the relationship between patients' average daily out-of-pocket buprenorphine cost and buprenorphine retention (at least 80 % days covered by buprenorphine) at three different thresholds (180, 360, and 540 days) and adherence (the number of days of buprenorphine coverage) within each retention threshold. Models controlled for patient demographic and clinical characteristics including age, sex, presence of other substance use disorders, psychiatric and pain diagnoses, and receipt of prescription medications. Results: A one dollar increase in daily out-of-pocket buprenorphine cost was associated with a 12-14 % decrease in the odds of retention and a 5-8 % increase in the number of days without buprenorphine coverage during each analyzed retention threshold. Conclusion: Recent policies have attempted to address supply-side barriers to MOUD treatment. This study highlights patient cost-sharing as a demand-side barrier to MOUD. While the average out-of-pocket buprenorphine cost is lower than two decades ago, this study suggests even at current levels such costs decrease retention and adherence among commercially insured patients. Efforts to address demand-side barriers could help maximize the health and social benefits of buprenorphine-based MOUD.