ESPE Abstracts

Background: The diagnosis of GH deficiency (GHD) is not straightforward in childhood and adolescence, requiring comprehensive clinical, anthropometric, biochemical, endocrine, and neuroradiological assessment. Although pharmacological GH stimulation tests are still considered the gold standard for GHD diagnosis, they are burdened by both poor specificity and side effects. Several studies have addressed the issue of sensitivity and specificity of IGFBP-3 assessment in the diagnosis of GHD, yielding conflicting data.

Aim: The objective of this study was to determine the value of IGFBP-3 assessment in the work-up of patients with short stature.

Methods and Results: We conducted a cross sectional retrospective study in a cohort of 455 subjects referred for short stature to our Unit. We performed GH stimulation tests and serum IGFBP-3 measurement in all subjects. We identified 25 GHD children (11F/14M; chronological age 5.5 ± 2.6 SDS) with height -2.9 ± 0.8 SDS and Tanner pubertal stage I at first evaluation. GHD diagnosis was based on the following anthropometric, endocrine, and radiological criteria: stature less than 2 SD score, delayed bone age (at least 1 yr), growth rate less than 25th centile, peak GH response to two different provocative tests less than 8 ng/ml to clonidine/arginine test (<19 ng/ml for GHRH + arginine test), brain magnetic resonance imaging (MRI) normal or positive for hypothalamus-pituitary abnormalities such as pituitary hypoplasia, stalk agenesis, and ectopic posterior lobe. Only 2 patients showed IGFBP-3 level < 3th centile (8%); in these two patients brain MRI abnormalities of pituitary gland were observed. Sensitivity and specificity of IGFBP-3 measurement were 17 and 97%, respectively.

Conclusion: Our results suggest that normal IGFBP-3 serum concentrations do not exclude GHD in more than 80% of patients. The low sensitivity of IGFBP-3 measurement makes it too inaccurate as a screening test in the work-up of children with short stature.