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Objectives:
To
evaluate body fat redistribution in antiretroviral-naïve patients treated
with atazanavir or efavirenz, each administered with fixed-dose zidovudine
and lamivudine twice daily.
Methods:
Antiretroviral-naïve patients received atazanavir 400 mg once daily or
efavirenz 600 mg once daily, each administered with fixed-dose zidovudine
and lamivudine (300 mg/150 mg) twice daily in the double-blind, prospective
trial BMS AI424‑034. In the metabolic substudy, dual-energy x-ray
absorptiometry and cross‑section computerized tomography scans were
performed at baseline and week 48.
Results:
Substudy results were based on 111 atazanavir- and 100 efavirenz-treated
patients. Baseline characteristics, including age, HIV RNA level, CD4 count,
and body mass index, were consistent between the substudy participants and
the overall study population (N=805). Increases from baseline (mean percent)
at week 48 were observed for appendicular (3%, atazanavir; 3%, efavirenz),
truncal (5%, atazanavir; 8%, efavirenz), and total body fat (5%, atazanavir;
5%, efavirenz) as well as for visceral (40%, atazanavir; 29%, efavirenz),
subcutaneous (19%, atazanavir; 5%, efavirenz), and total adipose tissue
(23%, atazanavir; 11%, efavirenz). The changes were significant on both
regimens (P<0.05). The mean weight gain from baseline was 1.2 Kg. No
changes in the ratios of appendicular-to-total body fat, truncal-to-total
body fat, or visceral-to-total adipose tissue were observed on either
regimen from baseline to week 48.
Conclusions:
Atazanavir and efavirenz produced comparable and proportional effects on
body fat distribution at 48 weeks when administered with fixed-dose
zidovudine and lamivudine to antiretroviral-naïve patients. The pattern of
fat increase observed on both regimens was consistent with weight gain and
not with the patterns for central adiposity (disproportionate increase in
truncal fat) or lipoatrophy (loss of appendicular fat) associated with the
development of lipodystrophy. |
