Impact of body weight on virological and immunological responses to efavirenz-containing regimens in HIV-infected, treatment-naive adults

OBJECTIVE: The prevalence of overweight and obesity is increasing among HIV-infected patients. Whether standard antiretroviral drug dosage is adequate in heavy individuals remains unresolved. We assessed the virological and immunological responses to initial efavirenz (EFV)-containing regimens in heavy compared to normal-weight HIV-infected patients. DESIGN: Observational European cohort collaboration study. METHODS: Eligible patients were antiretroviral-naive with documented weight prior to EFV start and follow-up viral loads after treatment initiation. Cox regression analyses evaluated the association between weight and time to first undetectable viral load ( 50 copies/ml) after initial suppression over 5 years of follow-up. Recovery of CD4 cell count was evaluated 6 and 12 months after EFV initiation. Analyses were stratified by weight (kg) group (I - 55, 80, 85, 90, 95). RESULTS: The study included 19 968 patients, of whom 9.1, 68.3, 9.1, 5.8, 3.5, and 4.3% were in weight groups I-VI, respectively. Overall, 81.1% patients attained virological suppression, of whom 34.1% subsequently experienced viral load rebound. After multiple adjustments, no statistical difference was observed in time to undetectable viral load and virological rebound for heavier individuals compared to their normal-weight counterparts. Although heaviest individuals had significantly higher CD4 cell count at baseline, CD4 cell recovery at 6 and 12 months after EFV initiation was comparable to normal-weight individuals. CONCLUSION: Virological and immunological responses to initial EFV-containing regimens were not impaired in heavy individuals, suggesting that the standard 600 mg EFV dosage is appropriate across a wide weight range.