Clonidine-stimulated growth hormone concentrations (cut-off values) measured by immunochemiluminescent assay (ICMA) in children and adolescents with short stature

Clonidine-stimulated growth hormone concentrations (cut-off values) measured by immunochemiluminescent assay (ICMA) in children and adolescents with short stature

To establish cut-off values for growth hormone concentrations using clonidine as a secretagogue and an immunochemiluminescent assay as the method of measurement and to analyze the response time as well as the influence of gender, nutritional status and pubertal stage. A total of 225 tests were perfo...

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Published in:Clinics (São Paulo, Brazil) Vol. 71; no. 4; pp. 226 - 231
Main Authors: de Fátima Borges, Maria, Teixeira, Flávia Carolina Cândida, Feltrin, Aline Karin, Ribeiro, Karina Alvarenga, Nascentes, Gabriel Antonio Nogueira, Resende, Elisabete Aparecida Mantovani Rodrigues, Ferreira, Beatriz Pires, Silva, Adriana Paula, Palhares, Heloísa Marcelina Cunha
Format: Journal Article
Language:English
Published: Brazil Elsevier España, S.L.U 01-04-2016
Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo
Faculdade de Medicina / USP
Elsevier España
Subjects:
Adolescent
Adrenergic alpha-2 Receptor Agonists - pharmacology
Body Height
Case-Control Studies
Child
Child, Preschool
Clinical Science
Clonidine
Clonidine - pharmacology
Female
GH Deficiency
Growth Disorders - blood
Growth Disorders - diagnosis
Growth Disorders - etiology
Growth Hormone - blood
Growth Hormone - deficiency
Human Growth Hormone - blood
Humans
Idiopathic Short Stature
Immunoassay - methods
Insulin-Like Growth Factor I - analysis
Luminescent Measurements - methods
Male
MEDICINE, GENERAL & INTERNAL
Prospective Studies
ROC Curve
Short Stature
Short Stature
Clonidine
GH Deficiency
Idiopathic Short Stature
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Summary:To establish cut-off values for growth hormone concentrations using clonidine as a secretagogue and an immunochemiluminescent assay as the method of measurement and to analyze the response time as well as the influence of gender, nutritional status and pubertal stage. A total of 225 tests were performed in 3 patient groups, categorized as group 1 (normal), group 2 (idiopathic short stature) and group 3 (growth hormone deficiency). Among the 199 disease-free individuals, 138 were prepubertal, and 61 were pubertal. Clonidine (0.1 mg/m2) was orally administered, and the growth hormone level was measured by immunochemiluminescent assay. The growth hormone peak and the difference between the growth hormone peak and the baseline level were then analyzed. Statistical analyses were performed using Student's t-test or the Mann-Whitney test and Kruskal-Wallis test followed by Dunn's post hoc test. Cut-off values were determined using a receiver operating characteristic curve. Group 1 and group 2 had no difference in growth hormone peak, gender, body mass index standard deviation score, or pubertal stage. Group 3 exhibited a significantly lower growth hormone peak than the other groups did. The receiver operating characteristic curve demonstrated that growth hormone concentrations ≥ 3.0 ng/mL defined responsiveness to clonidine. In total, 3.02% of individuals in group 1 and group 2 were considered false positive, i.e., these children lacked growth hormone deficiency and had a peak below 3.0 ng/mL. Clonidine-stimulated growth hormone concentrations ≥3 ng/mL, as measured by immunochemiluminescent assay, suggest responsiveness to the stimulus regardless of gender, body mass index standard deviation score or pubertal stage.
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ISSN:1807-5932
1980-5322
1980-5322
DOI:10.6061/clinics/2016(04)09