Homelessness, Substance Use Increase Risk for Post-Treatment HCV Reinfection

Homelessness and susbstance use are independent risk factors for post-treatment hepatitis C virus (HCV) reinfection, according to study results published in Clinical Infectious Diseases.

This retrospective analysis was conducted between January 2014 and March 2020 through the Boston Health Care for the Homeless Program. Researchers examined the post-treatment risk for HCV reinfection among a real-world cohort of individuals experiencing homelessness in Boston, Massachusetts. Participants were those receiving direct-acting antiviral therapy, and HCV reinfection was defined as the recurrence of HCV RNA at 12 weeks with HCV genotype switch or recurrent HCV RNA after achieving sustained virologic response. Participants were assessed at week 4, at the end of treatment, and at 12 weeks post-treatment. The primary outcome was the rate of incident HCV reinfection, calculated per 100 person-years (py) of follow-up via Poisson distribution. Risk factors associated with time to HCV reinfection were determined via Cox proportional hazards regression, with adjustments for age, sex, race/ethnicity, cirrhosis, HIV coinfection, recent substance use, and housing status.

Among 535 participants included in the final analysis, the median age was 49 years, 81% were men, 47% were non-Hispanic White, 70% had a mental health disorder, and 65% had opioid use disorder.

During a 617 py follow-up period, there were 74 incident HCV reinfections reported among 69 participants, 5 of which were second reinfections. Of these 69 participants, the median age was 42 years and 88% were men.

Cumulative factors associated with increased reinfection risk included unstable housing or homelessness vs stable housing (P =.001) and recent substance use (P =.001). Similar findings were noted in adjusted analyses, with reinfection risk significantly increased among participants experiencing homelessness vs stable housing (adjusted hazard ratio [aHR], 2.14; 95% CI 1.09-4.20; P =.026) and those with vs without recent substance use (aHR, 5.23; 95% CI, 2.25-12.13; P <.001).

The researchers noted that both homelessness at the time of HCV treatment and self-reported substance use prior to treatment were significant predictors of reinfection, irrespective of each other.

Limitations of this study include potential selection bias due to a lack of post-treatment outcome data. In addition, the rate of HCV reinfection may have been underestimated as HCV sequencing was not performed to confirm outcomes of reinfection vs viral relapse in participants with recurrent viremia of the same genotype.

According to the researchers, “Post-treatment clinical care should be included in the HCV cascade for early detection of reinfection and linage to retreatment.”