Cut-off limits of the peak GH response to stimulation tests for the diagnosis of GH deficiency in children and adolescents: Study in patients with organic GHD

Chiara Guzzetti, Anastasia Ibba, Sabrina Pilia, Nadia Beltrami, Natascia Di Iorgi, A. Rollo, Nadia Fratangeli, G. Radetti, Stefano Zucchini, Mohamad Maghnie, Marco Cappa, Sandro Loche

Research output: Contribution to journalArticlepeer-review

Abstract

Objective: The diagnosis of GH deficiency (GHD) in children and adolescents is established when GH concentrations fail to reach an arbitrary cut-off level after at least two provocative tests. The objective of the study was to define the optimal GH cut-offs to provocative tests in children and adolescents. Design: Retrospective study in 372 subjects who underwent evaluation of GH secretion. GH and IGF-I were measured by chemiluminescence assay in all samples. Receiver operating characteristic (ROC) analysis was used to evaluate the optimal GH cut-offs and the diagnostic accuracy of provocative tests. Methods: Seventy four patients with organic GHD (GH peak 10 μg/L to at least one test) were included in the study. The provocative tests used were arginine, insulin tolerance test (ITT) and clonidine. Diagnostic criteria based on cut-offs identified by ROC analysis (best pair of values for sensitivity and specificity) were evaluated for each test individually and for each test combined with IGF-I SDS. Results: The optimal GH cut-off for arginine resulted 6.5 μg/L, 5.1 μg/L for ITT and 6.8 μg/L for clonidine. IGF-I SDS has low accuracy in diagnosing GHD (AUC = 0.85). The combination of the results of provocative tests with IGF-I concentrations increased the specificity. Conclusions: The results of the ROC analysis showed that the cut-off limits which discriminate between normal and GHD are lower than those commonly employed. IGF-I is characterized by low diagnostic accuracy.

Original languageEnglish
Pages (from-to)41-47
Number of pages7
JournalEuropean Journal of Endocrinology
Volume175
Issue number1
DOIs
Publication statusPublished - Jul 1 2016

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

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