Coronary heart disease risk highest in HIV patients with fat loss?

Amongst HIV-positive individuals with fat redistribution, those with lipoatrophy appear to have the highest 10-year risk of coronary heart disease when their age, sex, cholesterol, blood pressure, diabetes and smoking status are compared with matched individuals in the Framingham Cohort, according to findings from a Massachusetts General Hospital study published in the April 1 edition of Clinical Infectious Diseases.

Dr Colleen Hadigan and colleagues recruited 91 individuals (65 male, 26 female) with self-reported body fat changes on HAART for prospective evaluation in December 1998. Individuals were excluded from the study if they had switched therapy within six weeks of study entry, if they had diabetes, were receiving medications likely to affect fat distribution such as steroids or the contraceptive pill, or if they were alcoholic.

Using baseline data each participant was matched with three Framingham Offspring Study participants, by age, sex, body mass index (n=273), and in a secondary analysis, with at least one FOS participant by waist: hip ratio. Thirty HIV-positive controls without lipodystrophy were also matched with FOS participants using the same exclusion criteria as for lipodystrophic individuals.

The ten year CHD risk was calculated using age, sex, total and HDL cholesterol levels, blood pressure, diabetes and smoking.

Significant differences in waist, hip and thigh circumference were noted between HIV-positive individuals with fat redistribution and controls, as well as in waist: hip ratio, but there was no significant difference in body mass index.

HIV-positive individuals had significantly higher total cholesterol levels (226 mg/dL vs 193mg/dL, p=0.0001) and significantly lower HDL cholesterol (37 vs 49mg/dL, p=0.0001).

Overall, the HIV-positive group had a significantly elevated 10-year risk of coronary events (angina, myocardial infarction or death due to CHD) than controls (7.4% vs 5.3%, p=0.002), and a significantly higher proportion of the HIV-positive group had a coronary heart disease risk of at least 10% (29.1 vs 12.8%, p=0.001). In both cases, this difference was restricted to male participants, with no significant differences detected in CHD risk between HIV-positive women and controls.

HIV-positive individuals with fat redistribution did not show an elevated CHD risk in comparison to the control group, and when individuals with lipodystrophy were matched by waist: hip ratio with the control group, the difference in CHD risk disappeared, suggesting that risk associated with lipodystrophy may be in part a function of central fat accumulation, a classic predictor of CHD risk and a characteristic of the metabolic syndrome in HIV-negative individuals.

However, when the investigators analysed CHD risk according to the type of fat redistribution experienced, a paradoxical result emerged. Despite the relatively small sample size, individuals who experienced lipoatrophy alone, with no central fat accumulation (n=15), had a significantly higher 10-year CHD risk than individuals who had experienced either central fat accumulation (n=15) or a mixed pattern of body fat changes (n=61). Furthermore, the 10 year CHD risk (p

Whilst individuals suffering lipoatrophy were more likely to smoke than other groups (40% vs 26.7% and 29.8%, n/s difference), and were slightly older (43.9 years (+/- 2.3) vs 39 years (+/- 1.5 years) than those with central fat accumulation, the investigators suggest that given its tendency to predispose to insulin resistance, diabetes and hyperlipidemia, subcutaneous fat loss in HIV disease may “substantially contribute to CHD risk.”