Comparison of body composition changes between atazanavir/ritonavir and lopinavir/ritonavir each in combination with tenofovir/emtricitabine in antiretroviral-naïve patients with HIV-1 infection.

BACKGROUND AND OBJECTIVE: Antiretroviral drug regimen choice may influence changes in body composition. The objective of this study was to compare changes in body composition between ritonavir-boosted atazanavir (ATV/r) and ritonavir-boosted lopinavir (LPV/r) over 96 weeks using data from a substudy of CASTLE, which compared once-daily ATV/r with twice-daily LPV/r, both in combination with tenofovir disoproxil fumarate/emtricitabine in treatment-naïve patients with HIV-1 infection. METHODS: We examined 224 patients (125 on ATV/r; 99 on LPV/r) at baseline, 48 and 96 weeks using dual-energy X-ray absorptiometry and computerised tomography. RESULTS: In the lowest baseline body mass index (BMI) group, there were significantly greater gains at week 96 for ATV/r than for LPV/r in subcutaneous adipose tissue and in visceral adipose tissue (VAT). By week 96, patients with lowest baseline CD4 cell counts on ATV/r had 28 % increases in VAT versus 14 % reductions for patients receiving LPV/r. Those with the lowest baseline BMI on ATV/r had 19 % increases in VAT versus reductions of 5 % for patients on LPV/r. In the highest baseline BMI group, the mean increase in triglycerides was 6 and 70 % in the ATV/r and LPV/r arms, respectively. Compared with baseline, an increase in proportion of patients with high waist circumference (WC)/high triglycerides at 96 weeks was noted in both treatment arms, but this increase was numerically greater with LVP/r (18 %) than with ATV/r (11 %). CONCLUSION: Truncal fat gains on ATV/r primarily led to increases in WC, which may reflect return to health, while on LPV/r increases in WC and triglycerides occurred. Changes in body composition with antiretroviral therapy are influenced by treatment choice and baseline characteristics.