Analysis of severe hepatic events associated with nevirapine-containing regimens: CD4+ T-cell count and gender in hepatitis C seropositive and seronegative patients.

Background: Nevirapine-containing regimens have been associated with a risk of significant elevations of liver transaminase levels. Higher risk in antiretroviral-naive populations has been related to gender and CD4+ T-cell count (women with CD4+ T-cell counts of > or =250/mm(3) or men with CD4+ T-cell counts of > or =400/mm(3), i.e. group at risk). However, recent studies do not confirm this association in HIV populations comprising patients who are antiretroviral-experienced. Moreover, the predictive value of gender and CD4+ T-cell count on the risk of raised transaminase levels has been poorly investigated in populations of patients co-infected with hepatitis C virus (HCV).

Methods: Analysis of HIV-positive patients receiving nevirapine-containing regimens for the first time was conducted. Grade > or =III hepatotoxicity (i.e. > or =5 x upper limit of normal in alanine aminotranferase or aspartate aminotransferase levels) was the primary endpoint. Univariate and multivariable Cox proportional hazard regression models were separately conducted among HCV-antibody (Ab)-positive and HCV-Ab-negative patients.

Results: Amongst 905 patients, 49% were HCV-Ab-positive and 79% were antiretroviral-experienced. Grade > or =III liver transaminase elevations developed in 7.1% of patients, accounting for an incidence of 2.47 (95% CI 1.97, 3.09) per 100 patient-years of follow-up. HCV-Ab reactivity was associated with a 3-fold increase in risk of developing relevant liver transaminase elevations (95% CI 1.75, 5.3; p < 0.001), whereas gender and CD4+ T-cell count did not impact significantly. When analysis was performed in HCV-Ab-negative patients, the outcome was independently correlated with the group at risk (hazard ratio [HR] 3.66; 95% CI 1.20, 11.14; p = 0.022). By contrast, in HCV-Ab-positive patients, the group at risk was not significantly associated with the outcome.

Conclusions: Most of the excess rates of relevant raised transaminase levels in patients prescribed nevirapine-containing regimens could be attributed to HCV co-infection. Gender and CD4+ T-cell count appeared to have a statistically significant impact on the risk of relevant transaminase level elevations in HCV-negative, but not in HCV-positive patients, probably due to a diluting effect of HCV. Incidence of hepatic events after nevirapine-containing regimens did not appear to be a major concern in our cohort of patients who were mainly antiretroviral-experienced and negative for HCV-Ab. Preferably, nevirapine should be avoided in HCV co-infected patients and in males with CD4+ T-cell counts of > or =400/mm(3) or females with CD4+ T-cell counts of > or =250/mm(3).