ESPE Abstracts

According to current recommendations, children with height SDS <-3.0, normal growth hormone (GH) peak in stimulation tests (stimGH) and severe IGF-I deficiency (IGFD) may be diagnosed with primary IGFD and treated with recombinant IGF-I. The need for direct confirmation of GH insensitivity is a matter of discussion. On the other hand, children born small for gestational age (SGA) with no catch-up growth are qualified to GH therapy despite normal GH secretion. The fact that some of them may fulfill the criteria of primary IGFD makes some confusion concerning the optimal treatment for them.

The aim of the study was to test the hypothesis that children with IGFD and excluded GH insensitivity may benefit during GH therapy despite normal stimGH and birth size appropriate for gestational age (AGA).

Retrospective analysis comprised 28 children (23 boys), age 13.0±2.2 years, including 6 cases of SGA and 22 of AGA, with height SDS <-3.0, stim GH >10.0 ng/ml and IGF-I SDS <-2.0, and with excluded GH insensitivity by significant IGF-I increase in generation test. The patients were treated with GH in standard doses for GHD up to final height (FH). The pre-treatment characteristics and the efficacy of treatment were compared between SGA and AGA.

There was no significant difference between AGA and SGA children in pre-treatment height SDS (-3.79±0.88 vs. -3.64±0.59, P=0.89), height velocity (HV) (3.8±0.8 vs. 3.4±1.0, P=0.34), stim GH (19.6±9.0 vs. 14.7±8.6 ng/ml, P=0.11) and IGF-I SDS (-3.08±0.98 vs. -2.60±0.39, P=0.37), as well as in IGF-I SDS at the end of generation test (-0.40±1.13 vs. -0.19±0.62, P=0.76). During 1^st year of treatment, in AGA and SGA similar increase was observed for both HV (up to 8.6±3.3 vs. 7.2±2.2 cm/year, P=0.18) and IGF-I SDS (0.56±1.56 vs. 0.42±0.52, P=0.92). The attained FH SDS was even better in AGA than in SGA (-1.66±0.94 vs. -1.82±0.87, P=0.53), similarly as the increase of FH SDS vs. pre-treatment height SDS (2.13±0.99 vs. 1.81±0.53, P=0.37).

It seems that children with height SDS <-3.0, normal stimGH and severe IGFD should not be diagnosed with primary IGFD if GH insensitivity is not documented. In case of AGA, they should not also be diagnosed with idiopathic short stature and remain untreated, as they may benefit during GH therapy at least similarly to SGA ones.