Mixed patterns of changes in central and peripheral fat following initiation of antiretroviral therapy in a randomized trial.

INTRODUCTION

Although peripheral fat loss is a consistent feature of HIV-associated lipodystrophy, less is known about whether changes in central and peripheral fat occur in tandem or independently over time. We examined intraindividual changes in dual-energy x-ray absorptiometry (DEXA) and anthropometry data over 64 weeks after initiation of antiretroviral therapy (ART).

METHODS

In ACTG 384, ART-naive subjects were randomized to receive didanosine and stavudine or zidovudine and lamivudine plus efavirenz, nelfinavir, or both. In the metabolic substudy A5005S (N= 329), waist, hip, thigh, and arm circumferences were measured in triplicate. DEXA scanning was performed in 157 subjects.

RESULTS

Individual changes in limb and trunk fat at week 64 correlated positively (R =.72, P <.001). Most subjects had directionally concordant changes in limb and trunk fat (36% gained and 32% lost in both regions). In 26%, trunk fat increased while limb fat decreased, whereas the reverse occurred in only 6% (P <.001). Changes in waist and hip circumferences also correlated positively (R =.62, P <.001). The proportion of subjects with waist/hip ratio more than .95 (men) or .90 (women) was 34% at baseline and 47% at week 64 (P =.003). In those who developed increased waist/hip ratio, 76% had increased waist circumference.

CONCLUSIONS

Individual results obtained by both anthropometry and DEXA show diverse patterns of fat gain and loss over 64 weeks after initiation of ART, but changes tended to occur in the same direction. Increased waist/hip ratio was predominantly associated with increased waist circumference. There was no evidence that central fat accumulation and peripheral fat loss are linked in most subjects.