BackgroundThis study examined associations between receipt of hepatitis C (HCV) treatment and retention in office-based opioid treatment (OBOT) care.MethodsWe conducted a retrospective cohort study of HCV-infected patients who initiated OBOT treatment between December 2015 and March 2021 to characterize HCV treatment and assess associations with OBOT retention. HCV treatment was characterized as no treatment, early treatment (< 100 days since OBOT initiation) or late treatment (≥ 100 days). We evaluated associations between HCV treatment and cumulative days in OBOT. A secondary analysis using Cox Proportional Hazards regression was done to determine the rate of discharge over time when comparing those who did versus did not receive HCV treatment as a time-varying covariate. We also analyzed a subset of patients retained at least 100 days in OBOT care and evaluated whether HCV treatment during that period was associated with OBOT retention beyond 100 days.ResultsOf 191 HCV-infected OBOT patients, 30% initiated HCV treatment, of whom 31% received early treatment and 69% received late treatment. Median cumulative duration in OBOT was greater among those who received HCV treatment (any: 398 days, early: 284 days and late: 430 days) when compared to those who did not receive treatment (90 days). Compared to no HCV treatment, there were 83% (95% CI: 33–152%, P < 0.001), 95% (95% CI: 28%-197%, p = 0.002 and 77% (95% CI: 25–153%, p = 0.002) more cumulative days in OBOT for any, early and late HCV treatment, respectively. HCV treatment was associated with a lower relative hazard for discharge/drop-out, although results did not meet statistical significance (aHR = 0.59;95% CI: 0.34–1.00; p = 0.052). Among the subset of 84 patients retained in OBOT at least 100 days, 18 received HCV treatment during that period. Compared to those who did not receive treatment within the first 100 days, those who received treatment had 57% (95% CI: -3%-152%, p = 0.065) more subsequent days in OBOT.ConclusionsA minority of HCV-infected patients received HCV treatment after initiating OBOT treatment, but those who did had better retention. Further efforts are needed to facilitate rapid HCV treatment and evaluate whether early HCV treatment improves OBOT engagement.