ESPE Abstracts

Background: Insulin-like Growth Factor-1 (IGF-1) is an amino acid peptide produced under the effect of Growth Hormone (GH), mostly secreted by the liver, which stimulates bone growth. IGF-1 levels have high specificity and low sensitivity for the diagnosis of Growth Hormone Deficiency (GHD). Higher IGF-1 levels are classically associated with a better response to growth hormone therapy. The aim of this study was to investigate the correlation between serum IGF-I levels at diagnosis and near adult height (AH), and the difference between AH and Target Height (∆AH-TH), in children evaluated for short stature.

Patients and Method: This retrospective analysis included 96 patients (61 male, 68 prepubertal, age 10,62±2,82) evaluated in our centre for short stature. 68 patients had GHD (peak of GH <10 µg/L after two stimulation tests with arginine, clonidine or insulin tolerance test, or <20 µg/L after GHRH+Arginine test) and were treated with recombinant human GH (20-25 µg/kg/die). 27 patients had a diagnosis of Idiopathic Short Stature (ISS, normal stimulated GH peak, no evidence of other cause for their shortness). AH was defined in a child whose height velocity (HV) fell ≤ 1 cm/year. Data are reported as mean ± standard deviation.

Results: At first evaluation height (H) SDS was -2,62±0,64, body mass index (BMI) SDS was -0,67± 1,21, IGF-1 SDS was -1,65±1,65, GH peak was 8,03±4,40 µg/L, and TH SDS was -1,53±0,78. AH SDS was -1,69±0,95, ∆AH-TH SDS was -0,18±1,00, difference between H SDS and TH SDS (∆H-TH) was -1,09±0,89, and difference between AH SDS and H SDS (∆AH-H) was 0,91±0,82. Pearson’s correlation showed a positive correlation in the whole group between IGF-1 SDS and H SDS (r= 0,247; P=0,015) and ∆H-TH (r= 0,387; P=0,0001); negative correlation between basal IGF-1 SDS and age at diagnosis (r= -0,292; P=0,004), TH SDS (r= -0,238; P=0,019) and ∆AH-H (r= -0,250; P=0,014); no correlation was between IGF-1 and sex (P=0,533), BMI SDS (P=0,070), pubertal status (P=0,638), HV SDS (P=0,165), GH peak (P=0,248), AH SDS (P=0,595), and ∆AH-TH SDS (P=0,199). In addition, no correlation was found between IGF-I levels at diagnosis and AH or ∆AH-TH when children with GHD and ISS were analysed separately.

Conclusions: The results of this study indicate that IGF-1 concentrations are not predictors of the pattern of growth in short children.