Importance: Hepatitis C virus (HCV) reinfection after curative treatment remains a concern for people who inject drugs.
Objective: To assess the incidence of HCV reinfection and associated risk factors.
Design, setting, and participants: This cohort study is a secondary analysis of a randomized clinical trial that was conducted across opioid treatment programs and community health centers in the US between September 2016 and August 2018. The current analyses were performed in March 2022. People who inject drugs who achieved sustained virologic response (SVR) were followed for up to 42 months.
Exposure: Patients were randomly assigned to receive modified directly observed therapy or patient navigation.
Main outcomes and measures: The primary outcome was rate of HCV reinfection. Change in reinfection rates over time was assessed using a Poisson regression model.
Results: A total of 415 participants (mean [SD] age, 44.7 [11.5] years; 302 male [72.8%]) achieved a SVR and had 1 or more post-SVR assessments for HCV RNA. Overall, 302 (72.8%) reported recent injection drug use, 192 (46.3%) were living in unstable housing, and 313 (75.4%) had received recent methadone or buprenorphine for opioid use disorder. The overall reinfection rate was 11.4 per 100 person-years at risk (95% CI, 8.7-14.7 per 100 person-years at risk) over 518 person-years of follow-up. Reinfection rates varied significantly across sites, ranging from 2.9 per 100 person-years at risk (95% CI, 0.1-16.3 per 100 person-years) to 25.2 per 100 person-years at risk (95% CI, 15.6-38.5 per 100 person-years at risk) (P = .006). There was a significant decrease in incident reinfection with increasing post-SVR follow-up (weeks 0-24, 15.5 per 100 person-years; 95% CI, 10.3-22.3 per 100 person-years; weeks 73-144, 4.3 per 100 person-years; 95% CI, 0.9-12.5 per 100 person-years; P = .008). Reinfection rates were lower for participants aged 40 years or older than for younger participants (adjusted incidence rate ratio, 0.32; 95% CI, 0.18-0.57) and for participants for whom methamphetamine was not detected in urinary drug screening compared with participants for whom methamphetamine was detected (adjusted incidence rate ratio, 0.41; 95% CI, 0.21-0.82). Participants who reported injection drug use within the preceding 3 months had higher risk of reinfection than those who did not have recent injection drug use (adjusted incidence rate ratio, 3.33; 95% CI, 1.86-5.97).
Conclusions and relevance: In this cohort study of people who injected drugs and were treated for HCV infection in community settings, reinfection was high in the period immediately after SVR but decreased significantly over time. These findings highlight the importance of early intervention to prevent reinfection.
Trial registration: ClinicalTrials.gov Identifier: NCT02824640.