Metabolic effects of discontinuing growth hormone treatment

Abstract

Aims-To evaluate the eVects of discontinuing growth hormone (GH) treatment on energy expenditure and body composition, which might help predict those most likely to benefit from early reintroduction of GH treatment in young adult life. Methods-Body composition was calculated from skinfold thicknesses and dual energy x ray absorptometry (DXA). Resting metabolic rate (RMR) and whole body bone mineral content (BMC) were also measured. Measurements were made before stopping treatment, at discontinuation of GH treatment, and two weeks, six months, and one year later in 11 adolescents with growth hormone deficiency (GHD) and five adolescents without GHD who were treated with GH. Measurements were compared with 10 healthy controls, in whom measurements were repeated one year later. Results-During the nine months before discontinuation of GH there were no changes in body composition, RMR, or BMC of patients with GHD, nor diVerences when compared with controls. RMR was reduced by 11.3 kJ/kg fat free mass two weeks after stopping GH in GHD patients and remained suppressed thereafter compared with controls. Percentage body fat increased by 4.3%/year in patients with GHD after discontinuing GH, whereas no changes were noted in control or non-GHD patients at one year. The patients experiencing the greatest reductions in RMR/kg fat free mass at six months showed the largest increases in body fat at one year. No change in BMC was noted in patients one year after stopping treatment. Conclusion-Important metabolic changes occur early after discontinuing GH treatment. In patients whose growth is complete, these changes might be used to predict those most likely to benefit from continuation of GH treatment into adult life. (Arch Dis Child 1999;80:517-523)

United States multicenter study of factors predicting the persistence of GH deficiency during the transition period between childhood and adulthood

“…Many studies have demonstrated deficits in somatic and metabolic maturation in GH-deficient individuals untreated during the transition period [1-4,6-17]. However, the determination of precisely which patients require ongoing GH therapy has been less clear, as many patients treated for childhood GHD do not fulfill diagnostic criteria for adult GHD after completion of linear growth.…”

“…Instead, GH potentially could be continued uninterrupted through the transition period (with appropriate dosage adjustment) to avoid the adverse changes in body composition, lipid profile, and cardiac function that may develop following discontinuation of GH [1-4,6-17] . Furthermore, patient care could potentially be improved by providing the family with a clear expectation at the initiation of childhood treatment, of the likelihood that GH treatment will be required in adulthood.…”

Energy expenditure in obesity associated with craniopharyngioma

“…Growth hormone can increase resting energy expenditure [21] and modulates thyroid hormone metabolism by increasing activation of thyroxine to tri-iodothyronine [22]. It increases lean mass and reduces body fat [23].…”

Limited Efficacy of Growth Hormone (GH) during Transition of GH-Deficient Patients from Adolescence to Adulthood: A Phase III Multicenter, Double-Blind, Randomized Two-Year Trial

“…However, studies specifically addressing the benefits of GH replacement therapy in adolescents who have finished growing, considered to be in transition, have so far yielded somewhat conflicting results. A small cohort of 11 adolescent subjects with GH deficiency had a decrease in resting energy expenditure and an increase in adiposity within a few weeks after discontinuation of GH, effects sustained for 1 yr of observation and not detected in healthy controls (30). Vahl et al (4) studied 19 adolescents with childhood-onset GH deficiency at the time of discontinuation of treatment, followed for 1 yr on either placebo or GH and then another year on GH in all subjects.…”