Body fat changes that occur after beginning antiretroviral treatment may be less frequent than some experts think, according to findings from two recent studies. Although Australian studies have reported an incidence of between 60% and 80% in patients who have received HAART for more than two years, a Spanish study published last week in The Lancet reported that less than 25% of people who started protease inhibitor therapy developed body fat changes within two years.
The study followed 494 individuals who started protease inhibitor therapy at the Hospital Clinic in Barcelona between 1996 and 1999. Body fat distribution was visually assessed by the clinician at baseline. During an average 18 months of follow up, 17% of patients developed lipodystrophy, and by Kaplan-Meier analysis it was estimated that 23% had some form of lipodystrophy after two years on therapy.
Three patterns of fat redistribution were reported amongst the 85 patients who developed lipodystrophy:
- Central obesity alone (21%)
- Peripheral fat wasting (34%)
- Mixed syndrome of fat gain and fat loss (45%)
Duration of exposure to d4T was associated with the risk of lipodystrophy accompanied by peripheral fat wasting, but even when patients who received d4T were excluded from the analysis, duration of exposure to HAART was still significantly associated with the likelihood of developing lipodystrophy with fat wasting, suggesting that the causes of peripheral fat wasting are multi-factorial and not solely linked to treatment with d4T.
A review of the Multicenter AIDS Cohort presented at the Eighth Annual Retroviruses Conference has added to the need for a revision of expectations about the frequency of lipodystrophy - and care in its diagnosis - especially in the context of advancing age. When researchers compared HIV-negative men, HIV-positive untreated men and HIV-positive men on HAART in their mid-forties and fifties, they found surprisingly high levels of body fat changes that could be classified as lipodystrophy in the HIV-negative men.
The MACS cohort was assembled in the mid-1980s and has tracked men ever since. The average age of its members is 47, and the study looked at 331 HIV-negative men and 537 HIV-positive men, of whom 390 were on HAART.
The researchers found that 25% of HIV-negative men had abdominal fat accumulations which could be classified as moderate or severe lipodystrophy, and 21% of the HIV-negative men had LDL cholesterol levels above 160mg/dL, compared to 12.3% of those on HAART. However, men on HAART were more likely to have very high triglyceride and glucose levels, and HIV-positive men were more likely to have low levels of HDL cholesterol (a feature of HIV disease). HIV-positive men on HAART were also more likely to have fat accumulation alongside peripheral fat wasting; this phenomenon was extremely rare among HIV-negative men.
References
Kingsley L et al. Prevalence of lipodystrophy and metabolic abnormalities in the Multicenter AIDS Cohort Study (MACS). Eighth Annual Retroviruses Conference, abstract 538, 2001.
Martinez E et al. Risk of lipodystrophy in HIV-1 infected patients treated with protease inhibitors: a prospective cohort study. The Lancet 357: 592-98, 2001.