Prediction of the growth response of short prepubertal children treated with growth hormone

The aim of this study was to identify predictors of the growth response to growth hormone (GH) during the first 2 years of GH treatment, using auxological data and the maximum GH response (GH_max) to provocation tests. The patients were 169 prepubertal short children (27F, 142M), with Gmax values ranging from 0 to 65 mU/1. Their mean age (± SD)was8.3 ± 2.4 years (range 3-13 years), mean height SDS –3.0 ± 0.7 (range –1.5 to –6.0SDS) and mean pretreatment height velocity was normal (± 0.0 SDS) (range -1.6 to + 0.9 SDS). The increase in height SDS during the first 2 years of GH treatment (0.1 U/kg/day) varied from 0.10 to 3.75 SDS, with younger children having a better growth response. Individual growth responses correlated (p < 0.001) with GH_max (r =–0.37), age (r= -0.35), 1-year pretreatment delta SDS (r = -0.25), mid-parental height SDS (r = 0.34), height SDS at start of treatment (r =–0.22) and difference between height SDS of an individual child at the onset of GH treatment and mid-parental height expressed in SDS (diff SDS) (r = –0.43). In a multiple stepwise linear regression model, diff SDS and log GH_max were found to be the strongest predictors of the magnitude of the growth response. In the short children in this study who exhibited a broad range of GH_max values, 33% of the growth response during the first 2 years of treatment could be predicted.