Baseline Characteristics and Effects of Growth Hormone Therapy over Two Years in Younger and Elderly Adults with Adult Onset GH Deficiency

Abstract

The effects of GH replacement in elderly GH-deficient (GHD) adults are not well known. In this prospective, single-center, open-label study, baseline characteristics and the effects of 2-yr GH replacement were determined in 24 GHD adults above 65 yr of age and in 24 younger GHD patients (mean age, 37 yr; range, 27-46 yr). All patients had adult onset disease, and both groups were comparable in terms of the number of pituitary hormonal deficiencies, gender, body mass index, and waist/hip ratio. Duration of hypopituitarism was, however, longer in the elderly patients. The mean maintenance dose of GH was 0.31 (sem, 0.03) mg/d in the elderly GHD patients and 0.44 (0.04) mg/d in the younger patients. The less marked response in IGF-I sd score, total body fat, and extracellular water in the elderly patients lost significance when the dose of GH was accounted for in the statistical analyses. Despite the lower dose in the elderly GHD group, these patients had a more marked reduction in waist/hip ratio and serum low-density lipoprotein-cholesterol level, and these differences remained also after correction for duration of hypopituitarism. There was no difference at baseline or in responsiveness in lean mass, bone mineral density, and glucose homeostasis. This study identifies elderly GHD adults as a GH-sensitive group in whom a low dose of GH can improve body composition and serum lipid profile without any significant impairment of glucose metabolism. GH replacement should therefore be considered in elderly GHD adults.