Growth hormone therapy in children with partial growth hormone deficiency. Are we treating the right patients?

Introduction
Diagnosis of growth hormone deficiency (GHD) in children with short stature, whose height is below –2SD for the population norm, is based on the assessment of growth hormone (GH) peaks in stimulation tests. However, cut-off values for GH secretion are arbitrary and vary in different centres. Indications for recombinant GH therapy remain disputable in children with GH concentrations between 5 and 10 ng/ml (pGHD).

Aim of the study
The aim of our study was to assess the effects of rhGH therapy in children with transient pGHD deficiency compared to untreated children with idiopathic short stature (ISS).

Material and methods
The study group comprised 54 patients at the mean age of 13.5 (SD 2.36) years, who were diagnosed as pGHD and treated with rhGH. The control group comprised 32 subjects with ISS matched for sex and age, untreated with rhGH.

Results
Mean final height was within the normal range for population norms in both groups. The average height gain was statistically significant at –1.3 SD (p < 0.001) for the study group and –1.02 SD (p ≤ 0.001) for the control group. However after exclusion of children with familial short stature (FSS) the height gains were, respectively, 1.41 SD ±0.67 for the study group and 1.22 SD ±0.77 for the control group, without statistical significance.

Conclusions
The results of our study did not show beneficial effects of rhGH treatment in children with pGHD as compared to untreated ISS subjects. Therefore, it is necessary to determine criteria other than arbitrarily established GH concentration for starting rhGH treatment in children with pGHD.