IGF-1 assessed by pubertal status has the best positive predictive power for GH deficiency diagnosis in peripubertal children

Author(s)

Inoue-Lima, Thais H. ^[1] ; Vasques, Gabriela A. ^{[1, 2]} ; Scalco, Renata C. ^{[1, 2]} ; Nakaguma, Marilena ^[1] ; Mendonca, Berenice B. ^[1] ; Arnhold, Ivo J. P. ^[1] ; Jorge, Alexander A. L. ^{[3, 1]}

Affiliation

^[1] Univ Sao Paulo, Fac Med, Hosp Clin, Unidade Endocrinol Desenvolvimento LIM 42, Sao Paulo - Brazil

^[2] Univ Sao Paulo, Fac Med, Hosp Clin, Unidade Endocrinol Genet LIM 25, Sao Paulo - Brazil

^[3] Univ Sao Paulo, USP LIM 25, Fac Med, Unidade Endocrinol Genet LIM 25, Hosp Clin, Av Dr Arnaldo 455, 5 Andar Sala 5340, BR-01246903 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: JOURNAL OF PEDIATRIC ENDOCRINOLOGY & METABOLISM; v. 32, n. 2, p. 173-179, FEB 2019.
• Web of Science Citations: 3

Abstract

Background: When evaluating peripubertal short stature patients, the interpretation of insulin-like growth factor 1 (IGF-1) levels based on chronological age (CA) can be inaccurate due to the influence of sex steroids and, presently, there is no evidence to support the assessment of IGF-1 values according to bone age (BA) and pubertal status (PS). Our objective was to assess the discriminatory performance of IGF-1 levels based on CA, BA and PS in the diagnosis of growth hormone (GH) deficiency. Methods: We evaluated IGF-1 levels from 154 peripubertal short stature patients classified as GH deficient (GHD, n = 23) or non-GHD (n =131). IGF-1 was assayed by a chemiluminescent immunometric assay and transformed into standard deviation scores (SDS) according to CA (IGF1-SDS-CA), BA (IGF-1-SDS-BA) and PS (IGF-1-SDS-PS). Results: The performances of IGF-1-SDS-CA, IGF-1-SDS-BA and IGF-1-SDS-PS in the receiver operator characteristics (ROC) curves were similar. There were greater accuracy and specificity of IGF-1-SDS-PS (98A% and 93.3%, respectively) and IGF-1-SDS-BA (92.7% and 90.1%, respectively) when compared to IGF-1-SDS-CA (65.6% and 69.5%, respectively). The post-test probability of the IGF-1-SDS was also improved when compared to PS and BA - 44.8% (IGF-1-SDS-PS), 16.8% (IGF-1-SDS-BA) and 5.1% (IGF-1-SDS-CA), with similar negative predictive values. Conclusions: The evaluation of IGF-1 levels based on CA has a higher sensitivity than those based on BA or PS, which justify its use as a screening tool. Additionally, IGF-1 assessed by PS has the best positive predictive power for GHD diagnosis in peripubertal age and could reduce the necessity of a second Gil stimulation test. (AU)

• FAPESP's process: 13/03236-5 - New approaches and methodologies in molecular-genetic studies of growth and pubertal development disorders
• Grantee: Alexander Augusto de Lima Jorge
• Support Opportunities: Research Projects - Thematic Grants