title: Evaluation of diagnostic accuracy of insulin-like growth factor (IGF)-I and IGF-binding protein-3 in growth hormone-deficient children and adults using ROC plot analysis.
abstract: We critically evaluated the diagnostic value of IGF-I and IGF-binding protein-3 (IGFBP-3) in GH deficiency (GHD) in children and adults using receiver operating characteristic (ROC) plot analysis. Sixty-six children (chronological age, 1.3-15 yr) were studied: 34 GHD and 32 idiopathic short stature (ISS). Ninety-two adults (chronological age, 18-70 yr) were also evaluated: 72 GHD, 34 of childhood onset (AGHD-CO), and 38 of adult onset (AGHD-AO); and 20 healthy volunteers. The SD score (SDS) for IGF-I was calculated from 596 normal subjects (212 children and 384 adults), and the SDS for IGFBP-3 was calculated from 350 normal subjects (212 children and 138 adults). The ROC plot showed that the best IGF-I SDS cut-off line was -1.65 for children [sensitivity (S), 68%; specificity (Sp), 97%, diagnostic efficiency (DEf), 81%], the cut-off line for AGHD was -1.65 for AGHD-CO (S, 91%; Sp, 100%; DEf, 94%), and the cut-off line for AGHD-AO was -1.80 (S, 81%; Sp, 100%; DEf, 88%). For IGFBP-3 SDS, the best cut-off line was -1.80 for children (S, 90%; Sp, 60%; DEf, 78%); it was -1.45 for AGHD-CO (S, 90%; Sp, 75%; DEf, 82%) and -0.90 for AGHD-AO (S, 90%; Sp, 68%; DEf, 77%). An accurate diagnosis was obtained using IGF-I SDS alone in GHD children 65%; ISS, 97%; AGHD-CO, 92%; AGHD-AO, 86%, with IGFBP-3 SDS alone in GHD children 60%; ISS, 90%; AGHD-CO, 75%; AGHD-AO, 68%. Considering both, an accurate diagnosis was obtained in GHD children 60%; ISS, 87%; AGHD-CO, 71%; AGHD-AO, 64%. In conclusion, our findings support the need to use cut-off lines expressed in SDS obtained using an appropriate statistical methodology for better characterization of the various clinical presentations. IGF-I proved to be more useful because of its good diagnostic efficiency and accuracy in both children and adults, whereas IGFBP-3 did not significantly contribute to the diagnosis of GHD.
authors.affiliation: Endocrinology Unit, Department of Medicine, Hospital T Alvarez, Buenos Aires C1406FWY, Argentina. hugofideleff@arnet.com.ar
authors.forename: Hugo R
authors.initials: HR
authors.lastname: Boquete
authors.forename: Patricia G V
authors.initials: PG
authors.lastname: Sobrado
authors.forename: Hugo L
authors.initials: HL
authors.lastname: Fideleff
authors.forename: Ana M
authors.initials: AM
authors.lastname: Sequera
authors.forename: Ana V
authors.initials: AV
authors.lastname: Giaccio
authors.forename: Martha G
authors.initials: MG
authors.lastname: Suárez
authors.forename: Gabriela F
authors.initials: GF
authors.lastname: Ruibal
authors.forename: Mirta
authors.initials: M
authors.lastname: Miras
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005069:Evaluation Studies as Topic; D005260:Female; D006130:Growth Disorders / Q000097:blood* / Q000175:diagnosis*; D019382:Human Growth Hormone / Q000172:deficiency*; D006801:Humans; D015592:Immunoradiometric Assay / Q000592:standards; D007223:Infant; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012016:Reference Values; D015203:Reproducibility of Results
chemical_list: D018972:Insulin-Like Growth Factor Binding Protein 3; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I