IGF1 for the diagnosis of growth hormone deficiency in children and adolescents: a reappraisal

Abstract

A number of studies have evaluated the role of IGF1 measurement in the diagnosis of growth hormone deficiency (GHD). This study aimed to evaluate th e accuracy and the best cut-off of IGF1 SDS in the diagnosis of GHD in a large coho rt of short children and adolescents. One-hundred and forty-two children and adolescents with GHD ((63 organic/ genetic (OGHD), 79 idiopathic (IGHD)) and 658 short non-GHD chi ldren (median age 10.4 years) were included in the analysis. The two groups were subdi vided according to age (G1 <6, G2 6 <9, G3 9 <12, G4 ≥12) and to pubertal status. Serum IGFI was measured by the same chemiluminescence assay in all samples and expressed as age- and sex-based SDS. Receiver operating characteristic (ROC) analysis was used to ev aluate the optimal IGF1 SDS cut-off and the diagnostic accuracy. Median IGF1 SDS was signific antly lower in the GHD than in non-GHD patients. The area under the curve (AUC) was 0. 69, with the best IGF1 cut-off of −1.5 SDS (sensitivity 67.61%, specificity 62.62%). The AUC was 0. 75 for OGHD and 0.63 for IGHD. The accuracy was better in the pubertal (AUC = 0.81) than the prepubertal group (AUC = 0.64). In our cohort, IGF1 measurement has poor accuracy in di scriminating GHD from non-GHD. Our findings confirm and reinforce the belief t hat IGF1 values should not be used alone in the diagnosis of GHD but should be interpreted in combination with other clinical and biochemical parameters.

Keywords

• growth hormone deficiency
• insulin-like growth factor 1
• children
• adolescents
• short stature