Auxological parameters associated with the diagnosis of growth hormone deficiency in children with short stature

Introduction
Diagnosis of growth hormone (GH) deficiency (GHD) requires confirmation by decreased GH peak in stimulation test (GHST). Despite physiological changes in GH secretion, the same cut-off for GH peak in different GHST is recommended throughout childhood. There are also reports indicating a high rate of false positive GHST results. The aim of the study was to identify auxological parameters relevant for the diagnosis of GHD based on the results of GHST in children with short stature.

Material and methods
Analysis included 1,592 children with short stature, in whom height, weight, body mass index (BMI), GH peak in two GHST and bone age (BA) were assessed. Diagnosis of GHD was based on GH peak in two GHST below 10.0 µg/l, otherwise the diagnosis was idiopathic short stature (ISS).

Results
Growth hormone deficiency was diagnosed in 604 patients (37.9%). There was no difference between GHD and ISS Groups in age, height and BA, while children with GHD had significantly lower (p < 0.001) BMI. The incidence of GHD depended on age, BA, height and BMI. After classifying the patients with respect to nutritional status (BMI SDS), GH peak was the lowest in children with overnutrition, while the highest in ones with undernutrition.

Conclusions
The assumption of the same cut-off value of GH peak for all GHST performed in children should be modified. Interpretation of GHST should be personalized.