The impact of glucocorticoid replacement on bone mineral density in patients with hypopituitarism before and after 2 years of growth hormone replacement therapy

Abstract

Context: Patients with hypopituitarism have reduced bone mineral density (BMD) and increased fracture risk. Objective: The aim of this study was to analyze the effects of glucocorticoid (GC) replacement on BMD before and after 2 years of GH therapy in hypopituitary patients. The main hypothesis was that patientson GC replacement demonstrate greater improvement in BMD when treated with GH. Design: This was a post hoc analysis of data from a prospective single-center study. Patients: Data on 175 adult patients with hypopituitarism and verified GH deficiency due to nonfunctioning pituitary adenoma were analyzed. Ninety-eight (56%) were GC insufficient, receiving a mean - SD hydrocortisone equivalent dose of 20.9 - 5.0 mg/d. Main Outcome Measure: BMD before and after 2 years of GH replacement therapy was measured by using dual-energy X-ray absorptiometry. Results: BMD at baseline did not differ between GC-sufficient and -insufficient patients, neither at lumbar spine nor femur neck. After 2 years on GH replacement, BMD increased in both groups. After adjustment for weight, age, gender, free T4 concentrations, change in IGF-I levels, and sex hormone treatment, GC sufficiency was associated with a greater increase in BMD at the femur neck (-T-score in GC insufficient patients 0.09-0.46, in GC sufficient patients 0.19-0.43; P-.05) but not at the lumbar spine. Conclusions: GH replacement therapy for 2 years increased BMD in hypopituitary patients. In contrast to our hypothesis, GC-insufficient patients receiving near physiological doses of hydrocortisone do not show a greater therapeutic response to GH therapy than their GC-sufficient counterparts. Copyright © 2014 by the Endocrine Society.