Socio-behavioral and geographic correlates of prevalent hepatitis C virus infection among young injection drug users in metropolitan Baltimore and Chicago

BackgroundHepatitis C virus (HCV) infection prevalence among young injection drug users (IDUs) differs substantially between cities in the United States (U.S.).MethodsBetween 2002 and 2004, IDUs aged 15–30 were recruited for the Third Collaborative Injection Drug User Study in five U.S. cities using respondent-driven methods. Our cross-sectional study examined correlates and geographic distribution of prevalent HCV infection (HCV+) from the Baltimore (n = 736) and Chicago (n = 586) study sites. We evaluated baseline socio-demographic and behavioral data collected from computer-assisted self-interviews and serological antibody testing for human immunodeficiency virus (HIV) and hepatitis A, B, and C.ResultsHCV prevalence was 53.0% in Baltimore and 13.7% in Chicago (p < 0.0001). Baltimore compared to Chicago participants were significantly (p < 0.05) more likely to be older, co-infected with HIV and other hepatitis viruses, reside in an urban area, inject primarily cocaine, inject in public settings, inject with used syringes and paraphernalia, and have been injecting longer; they were less likely to utilize syringe exchange programs. However, after accounting for socio-demographic and behavioral risk factors in multivariable logistic regression, city was the strongest predictor of HCV prevalence (Baltimore versus Chicago adjusted odds ratio = 3.5 [95% confidence interval, 2.2–5.6]). Geospatial analyses showed that almost half of all HCV+ participants in Baltimore resided within a 5-mile urban area, while Chicago participants were dispersed across the metropolitan area.ConclusionsThe disparate HCV prevalence between the two cities is only partially explained by individual-level factors. Future studies should examine the network configurations and injection partners’ characteristics of young IDUs.