The Impact of Current Opioid Agonist Therapy on Hepatitis C Virus Treatment Initiation Among People Who Use Drugs From the Direct-acting Antiviral (DAA) Era: A Population-Based Study.

BACKGROUND: Evidence that opioid agonist therapy (OAT) is associated with increased odds of hepatitis C virus (HCV) treatment initiation among people who use drugs (PWUD) is emerging. The objective of this study was to determine the association between current OAT and HCV treatment initiation among PWUD in a population-level linked administrative dataset. METHODS: The British Columbia Hepatitis Testers Cohort was used for this study, which includes all people tested for or diagnosed with HCV in British Columbia, linked to medical visits, hospitalizations, laboratory, prescription drug, and mortality data from 1992 until 2019. PWUD with injecting drug use or opioid use disorder and chronic HCV infection were identified for inclusion in this study. HCV treatment initiation was the main outcome, and subdistribution proportional hazards modeling was used to assess the relationship with current OAT. RESULTS: In total, 13 803 PWUD with chronic HCV were included in this study. Among those currently on OAT at the end of the study period, 47% (2704/5770) had started HCV treatment, whereas 22% (1778/8033) of those not currently on OAT had started HCV treatment. Among PWUD with chronic HCV infection, current OAT was associated with higher likelihood of HCV treatment initiation in time to event analysis (adjusted hazard ratio 1.84 [95% confidence interval {CI}, 1.50, 2.26]). CONCLUSIONS: Current OAT was associated with a higher likelihood of HCV treatment initiation. However, many PWUD with HCV currently receiving OAT have yet to receive HCV treatment. Enhanced integration between substance use care and HCV treatment is needed to improve the overall health of PWUD.

Factors associated with lost to follow-up after hepatitis C treatment delivered by primary care teams in an inner-city multi-site program, Vancouver, Canada.

BACKGROUND: Treatment of hepatitis c virus (HCV) with direct-acting-antivirals (DAAs) by family physicians in primary care and addiction settings may allow treatment expansion to inner-city populations, including people who inject drugs (PWID). Real-world data however, suggests high rates of non-attendance to SVR 12 testing. This study examines outcomes of HCV treatment delivered by family physicians working in interdisciplinary treatment programs, integrated into inner-city primary care clinics. METHODS: In this prospective cohort, participants completed baseline questionnaires, including questions on demographics and substance use. Participants were recorded as achieving a sustained virologic response (SVR 12) if HCV RNA was undetectable 12 weeks following end of therapy, and were recorded as lost to follow-up (LTFU) if they did not present for an HCV follow-up visit. SVR was calculated in intention to treat (ITT) as well as modified intention to treat (mITT) analysis, which excluded those who completed treatment but had no SVR 12 result. A logistic regression model assessed factors associated with LTFU. RESULTS: Of 138 individuals included in the analysis, 52% were on opioid agonist therapy (OAT), 75% reported a history of injection drug use (IDU), with 25% reporting IDU in the month prior to treatment initiation. ITT SVR across all sites and genotypes was 86% and mITT was 95%. There was a significant difference in mITT for those reporting recent IDU compared to those who did not (87% vs 99% p = 0.03). While 13% were LTFU at SVR 12, participants receiving OAT in the same clinic as HCV treatment were less likely to be LTFU (aOR 0.09(0.02-0.46)). CONCLUSION: HCV treatment by family physicians, along with interdisciplinary teams, can be successful in inner-city populations in the era of DAAs; however, follow-up after treatment is a challenge. Integrating OAT in the same location as HCV treatment may help to improve follow-up.