Risk factors for prevalent hepatitis C virus-infection among inmates in a state prison system in Mexico

To estimate the prevalence of HCV-infection and identify associated factors among inmates in the State Prison System of Guanajuato in Mexico (Sep-2011 to Feb-2012).

Cross-sectional, observational study in 10 prisons in the State of Guanajuato in Mexico (2011-2012). We offered HCV-testing and applied audio computer-assisted self-interviews to all adults imprisoned in the State Prison System. We used a complex survey analysis to estimate the distribution of variables and its corresponding 95% confidence intervals, taking into consideration the expected cluster effect by common characteristics within prisons. Inverse probability weights were applied to correct potential biased estimates arising from non-participation in accrual activities and non-response rates. We fitted multivariate logistic regression models to identify risk-behaviors associated to HCV-infection.

We included data of 2,519 participating inmates. Prevalence of HCV-infection was 4.9 (95%CI = 3.6-5.9). Most HCV-infected inmates were male (99%). Before being incarcerated, inmates with HCV-infection were more frequently tattooed, used and injected drugs more frequently, and were more likely to share materials for injecting, when compared with those non-infected. During incarceration, HCV-infected inmates got tattoos and used drugs more often than non-infected, including injecting-drugs and sharing materials. Injecting-drug use (OR = 7.6, 95%CI, 2.5-23.4), sharing materials for injecting-drugs (OR = 19.6, 95%CI, 4.7-81.7) and being tattooed at least once before incarceration (OR = 2.1, 95%CI, 1.1-3.9), but not during incarceration, were independently associated to HCV-infection.

The prevalence of HCV-infection among inmates in the State of Guanajuato in Mexico is considerably higher than in the general population. The most important risk factors for HCV in this inmate population were injecting-drugs and sharing materials for injections before incarceration. High-risk behaviors during imprisonment are very high particularly among those already infected. HCV diagnostic and treatment services, and harm-reduction programs for incarcerated injecting-drug users in Mexico should be integrated to control the HCV epidemic in Mexico.