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 GHmax , 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 GHmax and GH secretion
volume (r=0.883, p<0.01). Among the GH secretory indexes, GHmax
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 GHmax . The combination
of clinical and biochemical indexes may improve the pretreatment assessment of
response to rhGH treatment.
Keywords Growth hormone deficiency - Index of Responsiveness - GH stimulation test - GH secretory indexes