Effects of exercise training and metformin on body composition and cardiovascular indices in HIV-infected patients

Objective: To determine whether exercise training in combination with metformin improves cardiovascular risk indices and insulin in comparison to metformin alone among HIV-infected patients. Methods and design: We conducted a prospective, randomized, 3-month study of HIV patients on stable antiretroviral therapy with hyperinsulinemia and fat redistribution. Subjects received metformin alone or metformin and exercise training consisting of 1 h of aerobic and resistance training three times a week. Cardiovascular parameters, including blood pressure and endurance during sub-maximal stress testing, body composition, strength, insulin and other biochemical parameters were determined. Results: Thirty-seven patients were randomized and 25 subjects completed the study. Subjects receiving exercise training and metformin demonstrated significant decreases in median waist-to-hip ratio [-0.02 (-0.06, -0.01) (median (interquartile range) versus -0.01 (0.03, 0.02), P = 0.026], resting systolic [-12 (-20, -4) versus 0 (-11, 11), P = 0.012] and diastolic blood pressures [-10 (-14, -8) versus 0 (-7, 8), P = 0.001], increased thigh muscle cross-sectional area [3 (-3, 12) versus -7 (-11, 0), P = 0.015], and improved exercise time [3 (0, 4) versus 0 (-1, 1), P = 0.045] compared with subjects receiving metformin alone. Fasting insulin and insulin area under the curve decreased significantly more in the exercise and metformin group (P < 0.05). Lipids and resting lactate did not change significantly between treatment groups. Conclusions: These data demonstrate that exercise training in combination with metformin significantly improves cardiovascular and biochemical parameters more than metformin alone in HIV-infected patients with fat redistribution and hyperinsulinemia. Combined treatment was safe, well tolerated and may be a useful strategy to decrease cardiovascular risk in this population.