Incidence of liver injury after beginning antiretroviral therapy with efavirenz or nevirapine

Objective: To compare the incidence and define the risk factors associated with liver toxicity in patients beginning treatment with nevirapine (NVP) and efavirenz (EFZ). Method: This was a retrospective chart review of all HIV-infected patients starting any antiretroviral regimen containing at least two nucleoside analogues plus either NVP or EFZ between January 1998 and January 2000. Liver toxicity was defined as an increase in transaminase levels 5-fold above the upper limits of normal if they were normal at baseline or 3.5-fold above baseline levels if they were previously elevated. Results: Out of 298 patients included in the study, 162 received NVP and 136 EFZ. Overall, 75% were men, and 45% were coinfected with the hepatitis C virus (HCV). Median (interquartile range) time on follow-up was 10 (6-12) months. Liver toxicity was more frequently associated with NVP (12%) than with EFZ (4%) (p = .016). Overall, it was first recognized at a median time of 5.5 months (2.7-9.2) on therapy, with no differences between treatment arms. Both univariate and multivariate analyses identified the use of NVP, HCV coinfection, alcohol abuse, and female gender as independent risk factors for liver toxicity. Conclusion: Liver damage is three times more common in patients receiving NVP than in those taking EFZ. In both groups of patients, it is recognized late, after an average of 5.5 months on therapy. Coinfection with HCV, alcohol abuse, and female gender increase the risk for developing liver toxicity with both drugs.