Growth Hormone Treatment Improves Peripheral Muscle Oxygen Extraction-Utilization during Exercise in Patients with Human Immunodeficiency Virus-Associated Wasting: A Randomized Controlled Trial

Abstract

Abstract The arteriovenous oxygen difference (a-vO2 difference), a measure of peripheral muscle oxygen extraction-utilization during exercise, is reduced in antiretroviral-treated patients with human immunodeficiency virus (HIV), thus causing a shift in the cardiac output-oxygen consumption (Q-VO2) relationship. We investigated the impact of recombinant human GH (rhGH) treatment on a-vO2 difference and the Q-VO2 relationship during submaximal exercise by randomizing 12 HIV-infected patients (mean ± sem: age, 43.3 ± 1.5 yr; body mass, 69.5 ± 2.9 kg; body mass index, 22.4 ± 0.9 kg/m2; maximum oxygen consumption, 33.6 ± 1.5 ml/kg·min), with documented unintentional weight loss (≥10% within the preceding 12 months) despite antiretroviral therapy, to receive 3 months of rhGH (6 mg/d) in a double-blind, placebo-controlled, cross-over trial. We assessed Q (determined noninvasively using CO2 rebreathing), and subsequently a-vO2 difference, from Q-VO2 relationships. At study entry, the mean slope (8.1 ± 1.0 liters/min·1-liter increase in VO2) and intercept (3.1 ± 1.3 liters/min), generated from each patient’s Q-VO2 relationship, were greater and lower, respectively, than those reported for healthy individuals (6.0 and 4.0, respectively), thereby indicating a deficit in the a-vO2 difference. After 3 months of rhGH treatment, the slope decreased to 7.0, and the intercept increased to 3.5. After 1 month of rhGH treatment, the a-vO2 difference (at a VO2 of 1250 ml/min) significantly (P < 0.05) increased (17.1 ± 8.9%) from baseline (9.92 ± 0.51 ml/dl) and remained elevated (10.39 ± 0.48 ml/dl) after 3 months of treatment. No significant changes were seen with placebo. Therefore, treatment with rhGH leads to an improvement in peripheral muscle oxygen extraction-utilization and the Q-VO2 relationship during exercise in patients with HIV-associated wasting despite antiretroviral therapy.