Effect of growth hormone dose on bone maturation and puberty in children with idiopathic short stature

Context: GH at 0.22 mg/kg.wk has been shown to have no effect on pubertal onset or pace, whereas GH at 0.5 mg/kg.wk has been shown to advance pubertal onset and bone maturation. Objectives: Our objectives were to determine whether 0.37 mg/kg.wk GH advanced pubertal onset, pace, or bone maturation relative to 0.24 mg/kg.wk GH; whether 0.37 mg/kg.wk GH led to pubertal onset at an inappropriately early age; and whether age at start of GH therapy influenced pubertal onset. Design: We conducted a randomized, open-label study to final height. Patients: We studied children with idiopathic short stature. Intervention: Patients were treated with 0.24 mg/kg.wk, 0.24 increasing to 0.37 mg/kg.wk, or 0.37 mg/kg.wk. Main Outcome Measures: We assessed age at pubertal onset and rates of bone maturation, Tanner stage development, and increase in testicular volume (boys only). Results: For the primary comparison between the 0.24 and 0.37 mg/kg.wk dose groups, median ages of pubertal onset (in years) were similar (13.7 vs. 13.5 for boys and 11.7 vs. 11.4 for girls) and were greater than those for the general population for each sex. Age at start of GH therapy did not appear to influence pubertal onset for either sex. Rates of pubertal pace and bone maturation were not significantly different between the 0.24 and 0.37 mg/kg.wk dose groups for either sex. Conclusion: GH at 0.37 mg/kg.wk does not appear to accelerate pubertal onset, pace, or bone maturation compared with GH at 0.24 mg/kg.wk in patients with idiopathic short stature. From a clinical standpoint, our results suggest that the approved dose range of up to 0.37 mg/kg.wk GH does not lead to pubertal onset at an inappropriately early age.