Fat distribution in HIV-infected patients reporting truncal enlargement quantified by whole-body magnetic resonance imaging

Abstract

Background: Antiretroviral therapy has improved the prospects for people infected with HIV, but some develop a syndrome of profound body habitus and metabolic alterations that include truncal enlargement. Objective: The purpose of this study was to define the body-composition changes associated with this syndrome by using techniques with the power to estimate regional body composition. Design: We compared whole-body and regional skeletal muscle and adipose tissue contents measured by magnetic resonance imaging and dual-energy X-ray absorptiometry (DXA) in 26 HIV-infected patients and 26 matched control subjects. Twelve of the HIV-infected patients had evidence of truncal enlargement. Results: HIV-infected men and women who noted truncal enlargement had similar amounts of skeletal muscle and subcutaneous adipose tissue but greater visceral adipose tissue than HIV-infected patients without truncal enlargement; these values were larger in men (P < 0.001) than in women (P = 0.08). The ratio of visceral to subcutaneous adipose tissue was greater in both men (P < 0.02) and women (P = 0.05) with truncal enlargement. Two subjects with MRI-confirmed visceral adiposity syndrome (VAS) were not taking protease inhibitors. CD4⁺ lymphocyte counts were higher (P < 0.001) and plasma viral burdens tended to be lower (P = 0.08) in HIV-infected patients with VAS. Conclusions: There was significantly more visceral adipose tissue in the subgroup of HIV-infected patients with truncal enlargement than in those without this sign. VAS occurs in both men and women, is associated with higher CD4⁺ lymphocyte counts and lower plasma HIV viral burdens, and is not limited to those receiving protease inhibitor therapy.