Risk factors for HIV infection among patients infected with hepatitis C virus

OBJECTIVE: Human immunodeficiency virus and hepatitis C virus share the same routes of transmission. Currently, there is a high frequency of co-infection worldwide, especially among users of injectable drugs and in subjects with history of blood transfusions. The aim of the present study was to evaluate risk factors associated to human immunodeficiency virus infection in patients infected with hepatitis C virus. METHODS: We carried out an epidemiological case-control study, including 118 patients (cases) infected by both viruses and 233 patients (controls) infected only by the hepatitis C virus. Between January 1999 and November 200 1, patients responded to a questionnaire assessing sociodemographic and professional characteristics, and major risk factors for virus infection. After description and initial comparison, variables were evaluated by univariate analysis and then by multivariate logistic regression for variables selected through the maximum likelihood test. RESULTS: Co-infection was associated with female sex (OR=2.89; 95% Cl: 1. 167.08), being divorced/widow (OR=3.91; 95% Cl: 1.34-11.35), past or current use of illegal drugs (OR=3.96; 95% Cl: 1.55-10.13) and to the habit of sharing pipes or needles (OR=10.28; 95% Cl: 4.00-6.42). CONCLUSIONS: Among patients infected with hepatitis C virus, female sex is a risk factor for HIV infection after adjustment for the habit of sharing pipes and needles. Being divorced/widow, use of illegal drugs, and the habit of sharing pipes and syringes were associated to co-infection.