Chronic hepatitis C virus infection and increases in viral load in a prospective cohort of young, HIV-uninfected injection drug users.

BACKGROUND: Chronic hepatitis C (HCV) infection, defined as persistent RNA (viral load) for at least 6 months, accounts for up to 50% of all cirrhosis, end-stage liver disease and liver cancer cases. Moreover, elevated HCV viral load is consistently associated with high infectivity and poor therapy response. This study aims to identify modifiable behavioral correlates both chronic HCV infection and increases in viral load over time among injection drug users (IDUs).

METHODS: Cross-sectional and longitudinal analyses were performed using self-interview and serological data from a prospective cohort study (2002-2006) among young (age 18-35), HIV-negative, HCV therapy-naïve IDUs (n=113) from metropolitan Chicago, Illinois, USA.

RESULTS: After adjustment for age, gender and race/ethnicity, using drugs measured or mixed in someone else's syringe (odds ratio=2.7, 95% confidence interval: 1.1, 6.7) was associated with chronic (n=75, 66%) versus resolved (n=38, 34%) HCV infection status. Among chronically-infected IDUs, injecting with a new, sterile syringe infrequently (<1/2 half the time when injecting) compared to frequently (1/2 the time or more when injecting) was associated with increases in viral load over time after adjusting for age, gender, race/ethnicity and time effects.

CONCLUSIONS: Reductions in risky injection-related practices among young IDUs may ameliorate both the burden of chronic HCV infection-related liver disease and elevated viral load-related poor treatment response.