Body composition response following long-term GH replacement in adults with craniopharyngioma associated hypopituitarism
Y Liu, JK Powrie, L Breen, SM Thomas & PV Carroll
Patients with craniopharyngioma are frequently obese with a high prevalence of vascular morbidity. Many patients with treated craniopharyngioma have severe GH deficiency (GHD), which independently results in abnormal body composition and increased cardiovascular risk. This study investigated how GH treatment influences body composition in adults with treated craniopharyngioma and GHD.
Using the electronic database Diabeta3® we identified 50 patients with a history of craniopharyngioma. Of these, 15 (11 male, age 49.3±10.0 years, range 3765) received GH treatment for documented severe GHD for a minimum period of 5 years. Median age at diagnosis was 17 years (range 436). About 7/15 had received external beam radiotherapy as part of treatment for craniopharyngioma. Body composition was assessed using bioelectrical impedance at baseline and annually during GH treatment. Data was collected from patients notes and electronic databases. Whole-body weight for the subjects was 78.7±21.5 kg prior to commencement of GH (baseline), 79.4±18.1 kg at 1 year (P=0.63) and 81.9±17.6 kg after 5 years continuous GH replacement (P=0.15). The GH dose was 0.58±0.27 mg/day. Lean body mass was 53.4±11.0 kg at baseline, increasing to 54.7±10.7 kg at one year (P<0.05) and 56.5 kg±11.5 at 5 years (P<0.001). Fat mass did not change during GH treatment (25.3±16.0 kg at baseline, 25.2±13.6 kg at 1 year and 25.9±12.2 kg at 5 years). No significant change was recorded in fat percentage. No differences in response to GH in sub-groups based on gender or history of radiotherapy were evident.
Conclusion: Continuous GH replacement for 5 years is associated with an incremental improvement in lean body mass in this group of craniopharyngioma patients. However the benefits on fat percentage and fat mass seen in other GHD patients were not reproduced in this group. Further investigation is required to determine whether GH replacement results in sustained benefits in the adult with a history of craniopharyngioma.