Background:  Co-infection with hepatitis C virus (HCV) occurs in 15 to 30% of HIV-infected patients. Recent studies found disparate effects of HCV on mortality. We hypothesized that HIV/HCV-co-infected patients would have a higher death rate than patients with HIV alone and investigated risk factors for death in co-infected patients.

Methods:  We performed a retrospective cohort study of HIV-infected patients attending a public hospital HIV-specialty clinic who had their initial visit on or after January 1, 1997 and at least 2 visits in a year before the end of the study period (October 30, 2004). Patients were included in the HIV/HCV-co-infected group if they had a positive HCV EIA and an HCV RNA test was performed or if an HCV RNA test was positive. Deaths were verified by the Social Security Death Index. Causes of death were determined by review of hospitalization records or death certificates and categorized into hepatic, HIV-related, other medical cause, accidental or unknown. Using time dependent variables, a Cox proportional hazard model was constructed to determine predictors of death.

Results:  A total of 369 HIV/HCV-co-infected patients and 1461 patients with HIV alone met inclusion criteria. Of HIV/HCV-co-infected patients, 60 died (mortality rate of 3.8 per 100 person-years) compared with 120 deaths in patients not infected with HCV (1.9 per 100 person-years, p <0.0001). Among HIV/HCV-co-infected patients, the most common cause of death was HIV-related (19, 32%), followed by other causes including lung cancer and chronic obstructive pulmonary disease (15, 25%), and hepatic-related causes (14, 23%); 3 deaths were accidental (5%). At the time of death or censoring, 9 of 60 (15%) patients who died were receiving HAART, vs 244 to 309 (79%) of patients who were alive (RR = 0.08, 95%CI 0.04 to 0.16). In the multivariate analysis of co-infected patients, CD4 count <200 cells/mL (HR 2.1, 95% CI 1.2 to 3.9), total bilirubin >2 (HR 3.2, 95%CI 2.2 to 4.8), albumin <2.8 (HR 11.5, 95%CI 5.0 to 26.1) and ALT >twice upper limit of normal (HR 2.1, 95%CI 1.2 to 3.6) were significant risk factors for death.

Conclusions:  HIV⁺ patients co-infected with HCV had a higher death rate than those without HCV infection. Although HIV was the most common cause of death in co-infected patients, 23% of co-infected patients died of liver disease. Low CD4 count, markers of poor hepatic synthetic function and hepatic inflammation are significant predictors of death in HIV/HCV-co-infected patients, after controlling for HAART use.