Abstract
Background
Patients coinfected with hepatitis C virus (HCV) and HIV experience higher mortality rates than patients infected with HIV alone. We designed a study to determine whether risks for later mortality are similar for HCV-positive and HCV-negative individuals when subjects are stratified on the basis of baseline CD4+ T-cell counts.
Methods
Antiretroviral-naive individuals, who initiated highly active antiretroviral therapy (HAART) between 1996 and 2002 were included in the study. HCV-positive and HCV-negative individuals were stratified separately by baseline CD4+ T-cell counts of 50 cell/μl increments. Cox-proportional hazards regression was used to model the effect of these strata with other variables on survival.
Results
CD4+ T-cell strata below 200 cells/μl, but not above, imparted an increased relative hazard (RH) of mortality for both HCV-positive and HCV-negative individuals. Among HCV-positive individuals, after adjustment for baseline age, HIV RNA levels, history of injection drug use and adherence to therapy, only CD4+ T-cell strata of <50 cells/μl (RH=4.60; 95% confidence interval [CI] 2.72–7.76) and 50–199 cells/μl (RH=2.49; 95% CI 1.63–3.81) were significantly associated with increased mortality when compared with those initiating therapy at cell counts >500 cells/μl. The same baseline CD4+ T-cell strata were found for HCV-negative individuals.
Conclusion
In a within-groups analysis, the baseline CD4+ T-cell strata that are associated with increased RHs for mortality are the same for HCV-positive and HCV-negative individuals initiating HAART. However, a between-groups analysis reveals a higher absolute mortality risk for HCV-positive individuals.