Growth Hormone (GH) Dosing during Catch-Up Growth Guided by Individual Responsiveness Decreases Growth Response Variability in Prepubertal Children with GH Deficiency or Idiopathic Short Stature

Context: Weight-based GH dosing results in a wide variation in growth response in children with GH deficiency (GHD) or idiopathic short stature (ISS). Objective: The hypothesis tested was whether individualized GH doses, based on variation in GH responsiveness estimated by a prediction model, reduced variability in growth response around a set height target compared with a standardized weight-based dose. Setting: A total of 153 short prepubertal children diagnosed with isolated GHD or ISS (n = 43) and at least 1 SD score (SDS) below midparental height SDS (MPHSDS) were included in this 2-yr multicenter study. Intervention: The children were randomized to either a standard (43 mu g/kg.d) or individualized (17-100 mu g/kg.d) GH dose. Main Outcome Measure: We measured the deviation of height(SDS) from individual MPHSDS (diffMPH(SDS)). The primary endpoint was the difference in the range of diffMPH(SDS) between the two groups. Results: The diffMPH(SDS) range was reduced by 32% in the individualized-dose group relative to the standard-dose group (P < 0.003), whereas the mean diffMPH(SDS) was equal: -0.42 +/- 0.46 and -0.48 +/- 0.67, respectively. Gain in height(SDS) 0-2 yr was equal for the GH-deficient and ISS groups: 1.31 +/- 0.47 and 1.36 +/- 0.47, respectively, when ISS was classified on the basis of maximum GH peak on the arginine-insulin tolerance test or 24-h profile. Conclusion: Individualized GH doses during catch-up growth significantly reduce the proportion of unexpectedly good and poor responders around a predefined individual growth target and result in equal growth responses in children with GHD and ISS. (J Clin Endocrinol Metab 94: 483-490, 2009)