Impact of GH substitution on exercise capacity and muscle strength in GH-deficient adults: a meta-analysis of blinded, placebo-controlled trials.

Research paper by K Z KZ Rubeck, S S Bertelsen, P P Vestergaard, J O L JO Jørgensen

Indexed on: 11 Jun '09Published on: 11 Jun '09Published in: Clinical Endocrinology


Several but not all trials suggest that GH replacement in GH-deficient adults improves aerobic exercise capacity, whereas its effect on muscle strength is more dubious. However, a denominator of these studies is a low sample size.We systematically reviewed and analysed all randomized, double-blind, placebo-controlled trials on the effects of GH administration on aerobic exercise capacity and muscle strength in GH-deficient adults.Fifteen trials were identified from four databases. We conducted an analysis of effects on aerobic exercise capacity, performed on either a treadmill or a bicycle ergometer, muscle strength assessed by a dynamometer, and muscle mass assessed by computerized tomography.The total number of patients included was 306 and the duration of treatment ranged from 3 to 12 months. GH replacement significantly increased aerobic exercise capacity [8.9 ± 0.8%, (P < 0.001)] including VO(2) max [0.17 ± 0.02 l/min (P < 0.001)], as well as muscle volume [7.1 ± 1.6%, (P < 0.001)]. In contrast, muscle strength measured in 113 patients was not significantly increased [3.2 ± 2.2% (P = 0.15)].GH replacement in GH-deficient adults is associated with a significant positive effect on aerobic exercise capacity and muscle mass.