Growth Hormone Treatment Response: Associated Factors and Stimulated Growth Hormone Secretion Indices in Prepubertal Children with Idiopathic GH Deficiency.

Abstract

Introduction: This study aimed to examine the correlation between the growth response in prepubertal children with idiopathic growth hormone (GH) deficiency after 1 year of treatment with GH to the initial clinical and biochemical parameters. Additionally, the secretion dynamics of GH was also studied by analyzing the GH stimulation test profiles in relation to the GH treatment response.

Methods: This retrospective study included 84 prepubertal children (47 males and 37 females) with a definitive diagnosis of GH deficiency. The GH secretory indexes GH_max, GH secretion rate, and GH secretion volume were analyzed in relation to the response to recombinant human growth hormone (rhGH) treatment as defined by the index of responsiveness (IoR). Correlation and regression models were used to identify the best clinical and biochemical predictors to rhGH treatment. ResultsIoR was negatively correlated with the age (r=-0.607, p<0.01) and positively with the distance of child's height from its midparental height (MPH) r=0.466 (p<0.01) and pretreatment growth velocity (r=0.247, p<0.05). GH secretory indexes were correlated, and the highest association was observed between GH_max and GH secretion volume (r=0.883, p<0.01). Among the GH secretory indexes, GH_max was the best predictor of IoR (β coef. = -0.514, p<0.001) followed by the GH secretion volume (β coef. = -0.47, p<0.001) and GH secretion rate (β coef. = -0.367 p<0.001).

Conclusions: The age and the distance of child's height from its MPH are major predictors of GH treatment response in children with idiopathic GH deficiency. The calculation of the other GH secretory indexes GHSR and GHSV are not better predictors of response to GH than GH_max. The combination of clinical and biochemical indexes may improve the pretreatment assessment of response to rhGH treatment.