ESPE Abstracts

Introduction: Currently, there is no diagnostic gold standard for growth hormone deficiency (GHD). The diagnosis of GHD is based on the current consensus guidelines, which state that an inadequate GH level of 7 ng/mL during two growth hormone stimulation tests (GHSTs) is indicative of GHD. The primary objectives of this study were to assess the sensitivity and specificity of low IGF-1 levels in combination with a single insulin tolerance test (ITT) for diagnosing GHD.

Methods: This cross-sectional study analyzed data from 131 children aged 1-16 years with short stature who underwent GHSTs. We compared the diagnostic value of IGF-1 levels using a cut-off value of ≤ 0, -1 and -2 SD score, along with the results of a single ITT. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and the area under the curve (AUC) were evaluated.

Results: Among the 131 children, 98 (74.8%) had an IGF-1 SDS ≤ -1 (median -2.05, IQR -2.80 to -1.49), while 33 (25.2%) had an IGF-1 SDS level > -1 (median 0.08, IQR -0.70 to -0.46). GHD was diagnosed in 46 patients (46.9%) in IGF-1 SDS ≤ -1 group, and 14 patients (42.4%) in IGF-1 SDS > 1 group. Combining an IGF-1 level of ≤0 SDS, ≤ -1 SDS, or ≤ -2 SDS with the results of a single ITT yielded specificities of 71.1%, 66.7%, and 77.8%, respectively. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve was 0.94, 0.92, and 0.99, respectively.

Conclusion: When used in combination with the results of a single ITT, low IGF-1 values (≤ 0, ≤ -1, or ≤ -2 SDS) showed suboptimal diagnostic accuracy for GHD.