ESPE Abstracts

Background: Peak GH level during stimulation tests (STs) stands as an important parameter in growth prediction models and recently it was shown that timing of the peak value in glucagon stimulation test (GST) may be an important indicator of growth hormone deficiency (GHD).

Objective and hypotheses: To detect a possible relationship between timing of the peak value of GH during STs and the effectiveness of treatment with rhGH in children with idiopathic GH deficiency (iGHD).

Method: We retrospectively studied 92 patients with iGHD (57 boys, mean age at diagnosis: 9.93 years). Diagnosis was confirmed with two different STs, GST and clonidine stimulation test (CST). Auxological parameters were recorded and SD scores were calculated according to sex- and age- matched population. Observed and predicted (according to KIGS Prediction Model) height velocity (HV) during the first year of treatment and the index of responsiveness IoR were calculated for the prepuberdal children (n=65). Atypical GST was defined as that with peak GH value at time 0’, 30’, 60’ and 180’ whereas atypical CST that with peak timing at 0’, 30’ and 120’.

Results: Atypical GST was recorded in 18 patients (19.6%). IoR was lower in the prepubertal children with atypical GST (−1.81±0.67 vs −1.34±0.85 P=0.051). In the CST the 19 children who had atypical timing had significantly lower height SDS (−2.35±0.51 vs −2.07±0.51 P=0.032), lower target height SDS (−0.52±0.58 vs −0.5±0.72 P=0.02), and a significant lower IoR (−1.86±0.66 vs −1.35±0.84 P=0.047). When the patients were categorized according to the number of atypical tests, significant differences in the IoR were found (−2.09±0.68 with two atypical STs (n=6), −1.64±0.61 with one atypical ST (n=16) and −1.29±0.87 with no atypical ST (n=43), P=0.048).

Conclusion: The presence of atypical ST correlates with lower response in the rhGH treatment of prepubertal children with iGHD.