ESPE Abstracts

Background: GH secretion is classically assessed by provocative tests and, indirectly, by IGF-1 serum levels. However, their diagnostic accuracy is low. The aim of the study was to evaluate the adult height (AH) in short patients with IGF-1 ≤-1,5 SDS.

Method: 52 short patients (height-SDS -2.6 (-3.1- -2.3), age 12.2 (10.2-13.7) y, 36 boys), with low height velocity(HV)-SDS (-1.6 (-3.2- -0.9)) and IGF-1 ≤-1,5 SDS (-2.2 (-2.8- -1.9)) were included in this retrospective analysis. The case group consisted of 24 patients (13 boys) with non-permanent, idiopathic, and isolated growth hormone deficiency (GHD, low peak GH after two provotative tests, <10 µg/l with Arginine, Insuline tolerance test, and Clonidine or <20 µg/l with GHRH+Arginine; normal MRI; normal GH and/or IGF-1 concentrations at near AH). These patients were treated with GH (25 µg/kg/die) until the near AH was achieved. The control group consisted of 28 patients (23 boys) with idiopathic short stature (normal peak GH after the provocative test, no evidence of other cause for their shortness). Values are reported as median (interquartile range).

Results: The AH-SDS, the ∆ AH-SDS – H-SDS and the ∆ AH-SDS – Target height(TH)-SDS were similar in both groups (-1.6 (-2.5 - -0.2), -1.8 (-2.6 - -1.1), P=0.3; 1.3 (0.5-2.2), 1 (0.5-1.5), P=0.08; -0.3 (-1.2 – 0.5), -0.2 (-0.9 – 0.5), P=0.7; respectively in cases and controls). BMI-SDS, HV-SDS, and pubertal stage were lower in cases than in controls, while TH-SDS was lower in controls. Age and IGF-1 SDS were similar in both groups. The same analysis performed including only the 41 subjects born adeguate for gestational age with normal BMI (14 cases and 27 controls), confirmed that the AH-SDS, the ∆ AH-SDS – H-SDS and the ∆ AH-SDS – TH-SDS were similar in both groups (-2 (-3 - -1.6), -1.8 (-2.6 - -1.2), P=0.52; 1.1 (0.3-1.5), 1 (0.5-1.4), P=0.13; -0.8 (-1.5 – -0.1), -0.3 (-0.9 – 0.5), P=0.59; respectively in cases and controls). Age, gender, BMI-SDS, HV-SDS, IGF-1 SDS, IGFBP-3 SDS, bone age, and pubertal stage, were similar in both groups.

Conclusions: In this study, both treated patients with idiopathic GH and not-treated patients with idiopathic short stature reached the same AH within TH, with similar height-SDS gain. Thus, the efficacy of treatment with GH in these patients is questionable. This could be due to the low accuracy of provocative tests and IGF-1 measurement in the diagnostic process of GHD, leading to a misdiagnosis of idiopathic short stature as GHD.