Differential Effects of Metformin and Exercise on Muscle Adiposity and Metabolic Indices in Human Immunodeficiency Virus-Infected Patients

The HIV-lipodystrophy syndrome is associated with fat redistribution and metabolic abnormalities, including insulin resistance (IR). The mechanisms and treatment strategies for IR in HIV-lipodystrophy are unclear, but data suggest that intramuscular lipids contribute to IR in this population. We previously showed that metformin and exercise improve hyperinsulinemia more than metformin alone in HIV-lipodystrophy. Now we investigate the effects of these treatment strategies on thigh muscle adiposity measured by computed tomography and additional body composition measures. Twenty-five HIV-infected patients on stable antiretroviral therapy with hyperinsulinemia and fat redistribution participated in a prospective, randomized, 3-month study of metformin alone or metformin and resistance training three times a week. Thigh muscle adiposity decreased significantly more as shown by increased muscle attenuation [2.0 (range, 0.5–5.0) vs. −1.0 (–3.5–0), P = 0.04] and sc leg fat tended to decrease more [–3.3 (–7.5–4.3...