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

To determine whether exercise training in combination with metformin improves cardiovascular risk indices and insulin in comparison to metformin alone among HIV-infected patients.

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.

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.

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.