Background: Lipodystrophy, or more specifically, fat redistribution (subcutaneous fat loss and/or visceral fat accumulation) is thought to be a complication of the severity and duration of HIV infection and HAART, associated with both nucleoside reverse transcriptase inhibitors (NRTIs) and protease inhibitors. In a previous analysis of this sub-study, the results reflected loss of subcutaneous fat in all 3 regimens. This analysis assessed the relative NRTI contribution on fat loss over a 2–3 yr period.

Methods: Non-randomized, cross-sectional, post-hoc sub-study of DMP 266-006 comparing 3 different regimens in therapy-naïve subjects: efavirenz (EFV) + zidovudine (ZDV) + lamivudine (3TC), indinavir (IDV) + ZDV + 3TC, and EFV + IDV. Consenting subjects underwent abdominal CT scans including a section at the level of the umbilicus or fourth lumbar vertebra. CT scans were performed locally at the next scheduled study visit with a follow-up scan 1 yr later. An independent, central reader read all scans in a blinded fashion. We compared changes in fat redistribution of patients receiving NRTIs versus an NRTI-sparing regimen. Comparisons were made using the Wilcoxon test.

Results: A total 373 subjects enrolled in this sub-study. Demographic and baseline characteristics of the 2 groups were comparable. The median time across groups from study start to first scan was 738 days and to the follow-up scan, 1,106 days; 277 subjects had both first and second scans. The median changes in subcutaneous fat between the first and second scans can be found in the chart below:

Subcutaneous Fat Changes (median values in cm2)
	1st Scan	2nd Scan	Median Change	p-value between arms
NRTI-CONTAINING regimens ZDV + 3TC + IDV OR EFV n = 188	268.58	140.85	-108.98*	> 0.05
NRTI-SPARING regimen EFV + IDV n = 89	331.07	185.25	-117.47*

* Median change in subcutaneous fat between 1^st and 2^nd scan (p < 0.05).

Conclusions: These data show that subcutaneous fat loss in patients receiving NRTIs was not significantly different than those observed in the NRTI-sparing arm, suggesting that NRTIs were not exclusively associated with fat loss in this study.