Eight years of growth hormone treatment in children with Prader-Willi syndrome: maintaining the positive effects.

BACKGROUND: The most important reason for treating children with Prader-Willi syndrome (PWS) with GH is to optimize their body composition. OBJECTIVES: The aim of this ongoing study was to determine whether long-term GH treatment can counteract the clinical course of increasing obesity in PWS by maintaining the improved body composition brought during early treatment. SETTING: This was a multicenter prospective cohort study. METHODS: We have been following 60 prepubertal children for 8 years of continuous GH treatment (1 mg/m(2)/d ≈ 0.035 mg/kg/d) and used the same dual-energy x-ray absorptiometry machine for annual measurements of lean body mass and percent fat. RESULTS: After a significant increase during the first year of GH treatment (P < .0001), lean body mass remained stable for 7 years at a level above baseline (P < .0001). After a significant decrease in the first year, percent fat SD score (SDS) and body mass index SDS remained stable at a level not significantly higher than at baseline (P = .06, P = .14, resp.). However, body mass index SDSPWS was significantly lower after 8 years of GH treatment than at baseline (P < .0001). After 8 years of treatment, height SDS and head circumference SDS had completely normalized. IGF-1 SDS increased to +2.36 SDS during the first year of treatment (P < .0001) and remained stable since then. GH treatment did not adversely affect glucose homeostasis, serum lipids, blood pressure, and bone maturation. CONCLUSION: This 8-year study demonstrates that GH treatment is a potent force for counteracting the clinical course of obesity in children with PWS.