Session: SUN 624-646-Growth: Clinical Trials & Observational Studies
Poster Board SUN-638
Patients and methods:This was a retrospective study in 629 short children and adolescents (402 M and 227 F, aged 2-17.8 yr) who underwent GH secretion studies for short stature. All underwent at least one test that was repeated if GH peak was <10 µg/L. IGF-I was also measured in all children. GHD was diagnosed in children with two GH peaks <10 µg/L (192 GHD and 400 controls). GH and IGF-I were measured by chemiluminescence assay in all samples. ROC analysis was used to evaluate the diagnostic accuracy of the tests. ROC analysis was repeated also assuming 7 µg/L as a cut-off for the diagnosis of GHD (111 GHD and 518 controls).
Results: ROC analysis showed that at a cut-off levels of 7 µg/L the diagnostic accuracy was better for Arg (AUC=0.9, Sensitivity=100%, Specificity=72.6%, vs AUC=0.87, Sensitivity=100%, Specificity=63.1%), ITT (AUC=0.9, Sensitivity=100%, Specificity=62.6%, vs AUC=0.87, Sensitivity=100%, Specificity=49.7%) and SS (AUC=0.96, Sensibility=100%, Specificity=88.9%, vs AUC=0.93, Sensitivity=100%, Specificity=84.3%). The diagnostic accuracy of Clo was better at a cut-off of 10 µg/L (AUC=0.99, Sensibility=100%, Specificity=97.2%, vs AUC=0.98, Sensitivity=100%, Specificity=89.8%). ROC analysis showed that IGF-I has low accuracy in the diagnosis of GHD using both cut-offs (AUC=0.66 at a cut-off of 7µg/L and AUC=0.61 using peak GH cut-off of 10 µg/l).
Conclusions: The use of peak GH cut-off limit of 7 µg/l improves the diagnostic accuracy of Arg, ITT and SS while the diagnostic accuracy of Clo was better at a cut off of 10 µg/L. SS showed the best accuracy at both cut-offs. IGF-I is characterized by low diagnostic accuracy. These results suggest that the choice of a cut-off limit of the GH peak for the diagnosis of GHD might be dependent on the type of stimulation test.
Nothing to Disclose: CG, AI, SP, NB, ND, AR, GR, SZ, MM, SL
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