Housing Stability and Hepatitis C Infection for Young Adults Who Inject Drugs: Examining the Relationship of Consistent and Intermittent Housing Status on HCV Infection Risk

Background: Housing status affects drug-using behaviors, but less is known about the relationship between housing patterns and hepatitis c virus (HCV) infection. Methods: HCV-negative young people who inject drugs (PWID) were enrolled into a prospective cohort (2003-2019) with quarterly study visits. We used Cox regression to estimate the independent association of recent housing status (housed vs. unhoused, housing stability, and housing trajectory), on HCV incidence. Findings: Among 712 participants, 245 incident HCV infections occurred over 963·8 person-years (py) (cumulative incidence: 24·4/100py). An inverse relationship between time housed and HCV incidence was observed (always unhoused: 45·0/100py, 95% Confidence Interval (CI): 37·1, 54·5; variably housed: 18·0/100py, 95% CI: 15·0, 21·3; and always housed: 7·0/100py, 95% CI: 3·0, 17·3). In Cox regression models controlling for confounders, those unhoused versus housed at baseline had a 1·9-fold increased infection risk (95% CI: 1·4, 2·6). Those always unhoused versus always housed had a 1·5-times greater risk of HCV (95% CI: 1·0, 2·3), and those variably housed had a lower risk (adjusted relative hazard: 0·05, 95% CI: 0·3, 0·9) with a similar trend for those being housed for less time. Interpretation: For this group of PWID, our findings indicate that some frequency of residential housing may protects HCV infection. Funding Statement: NIH/NIDA Grant R01DA16017, NIH/NIDA Grant K01DA037802. Declaration of Interests: The authors state that they do not have any conflicts of interest related to this work. Ethics Approval Statement: This study was reviewed by the Institutional Review Board at the University of California, San Francisco (#10-00063). Participants completed written consent.