A 10-year, prospective study of the metabolic effects of growth hormone replacement in adults

Context: Only a few studies have investigated the effects of GH replacement in adults for more than 5 yr. Objective/Design/Patients: In a prospective, open-label, single-center study, the effects of 10-yr GH replacement were determined. Eighty-seven consecutive patients (52 men and 35 women), with a mean age of 44.1 (range 22-74) yr with adult-onset GH deficiency (GHD) were included. Results: The initial mean dose of GH (0.98 mg/d) was reduced during the study and at yr 10 was 0.47 mg/d. The mean IGF-I SD score increased from -1.81 at baseline to 1.29 at study end. The absolute reduction in total body fat was transient. However, after correction for age and sex using a four-compartment model, the reduction in body fat was sustained during the 10-yr study period. There was a sustained improvement in serum lipid profile and after 10 yr, and blood glycosylated hemoglobin level was reduced. The treatment responses in IGF-I SD score, serum high-density lipoprotein cholesterol level, and body composition as measured using dual-energy x-ray absorptiometry were more marked in men, whereas women had a more marked reduction in blood glycosylated hemoglobin level. Conclusion: The effect on the absolute amount of body fat was seen early and was transient, which could be due to the normal aging of the patients. The effects on metabolic indices were detected later, but they were sustained and even progressive throughout the study period.