GH Dose Reduction Maintains Normal Prepubertal Height Velocity after Initial Catch-Up Growth in Short Children

Abstract

Context GH responsiveness guides GH dosing during the catch-up growth (CUG) period; however, little is known regarding GH dosing during the prepubertal maintenance treatment period. Objective To evaluate whether SD score (SDS) channel parallel growth with normal height velocity can be maintained after CUG by reducing the GH dose by 50% in children receiving doses individualized according to estimated GH responsiveness during the catch-up period. Design and Settings Prepubertal children (n = 98; 72 boys) receiving GH during CUG (GH deficient, n = 33; non-GH deficient, n = 65), were randomized after 2 to 3 years to either a 50% reduced individualized dose (GH RID; n = 27; 20 boys) or unchanged individualized dose (GH UID; n = 38; 27 boys). Another 33 children (25 boys) continued a standard weight-based dose [43 μg/kg/d (GH FIX)]. Main Outcome Measures The primary endpoint was the proportion of children with "height SDS within ±0.3 at 1 year after GH dose reduction compared with two control groups: GH UID and GH FIX. The hypothesis was that height SDS could be maintained within ±0.3 with a reduced individualized GH dose. Results For the intention-To-Treat population at 1 year, 85% of the GH RID group maintained "height SDS within ±0.3 vs 41% in the GH UID group (P = 0.0055) and 48% in the GH FIX group (P = 0.0047). The "IGF-I SDS in the GH RID group was-0.75 ± 1.0 at 3 months (P = 0.003) and-0.72 ± 1.2 at 1 year compared with the GH UID group (0.15 ± 1.2; P = 0.005) and GH FIX group (0.05 ± 1.0; P = 0.02). Conclusions Channel parallel growth (i.e., normal height velocity) and IGF-ISDS levels within ±2 were maintained after completed CUG using a 50% lower individualized dose than that used during the CUG period.