It is still unknown whether lipoatrophy (fat loss) and increases or decreases in visceral adipose tissue (VAT) are part of a single process or take place independently. If the two are part of a single process, then improvements in lipoatrophy should inversely correlate with changes in VAT and risk factors for improvements in each should be similar.

Researchers at St Vincent’s Hospital in Sydney, Australia assessed long-term data from 2 randomized studies: MITOX (a switch from d4T [n=85] or AZT [n=26] to abacavir for 24 weeks), and ROSEY (rosiglitazone [RSG; n=53] or placebo [n=55]).

Results

At weeks 48 and 72, there was a significant, although relatively weak, positive correlation between the changes in limb fat mass and VAT.

Limb fat increased by 0.5kg in only 23%, 33% and 41% of patients at 24, 48 and 72 weeks, respectively.

The only baseline parameter significantly correlated with a 0.5kg increase in limb fat was higher baseline body mass; increase in VAT at week 72 was independently associated with 0.5kg increase in limb fat (P=0.001).

In contrast, independent risk factors at baseline for a decrease in VAT were higher limb fat mass (P<0.0001), lower HDL-C (P=0.002) and higher insulin (P=0.03), as well as a greater decrease in limb fat to week 72 (P<0.0001).

Changes in subcutaneous abdominal fat also correlated positively with change in limb fat mass (P=0.001).

In conclusion, the study authors write, “An increase in limb fat in men recovering form lipodystrophy is not associated with a reduction in VAT, but rather an increase.” They also noted that changes in VAT and limb fat have different risk factors.

“Both [these] findings indicate that lipoatrophy and visceral obesity are at least partially independent processes,” write the investigators.

Finally, they conclude, “Lipoatrophy improved in 50% of patients after 18 months and was less likely in those with lower BMI.”

12/09/05

Reference
H Wand and others. Increase in limb fat after nucleoside analogue cessation is not associated with decreased visceral fat and has different risk factors. Abstract 3. 7th International Workshop on Adverse Drug Reactions and Lipodystrophy in HIV. November 13-16, 2005, Dublin, Ireland. Antiviral Therapy 2005; 10:L5.