Three years of growth hormone treatment in growth hormone-deficient adults: near normalization of body composition and physical performance

Abstract

Growth hormone (GH) replacement therapy in several controlled short-term trials have shown unanimous beneficial effects on body composition and other features. To evaluate more long-term effects we report data from 3 years of uninterrupted GH therapy in 10 GH-deficient adults who had all completed a previous double-blind placebo-controlled study and who also had been studied after 16 months of open GH therapy. No further increase in linear height was observed. The initial increase in thigh muscle volume was maintained after 3 years of GH therapy. A slight increase in body weight and thigh fat volume was recorded. Exercise capacity and isometric muscle strength were increased significantly compared to the initial placebo period. This was associated with stabilized levels of resting heart rate and blood pressure. Glycosylated hemoglobin levels were normal and did not change during the study. A standard oral glucose tolerance test performed at the end of the study revealed no evidence of glucose intolerance. No side-effects were reported. Compared to an age- and sex-matched group of healthy untreated subjects, thigh muscle volume, exercise capacity and isometric muscle strength had become normalized from subnormal levels after 3 years of GH therapy. We conclude that long-term GH replacement therapy in GH-deficient adults is associated with preserved beneficial effects on body composition and physical performance, resulting in a near normalization of several previously abnormal features and adding new merits to this treatment modality.