Background: Recently, the American Diabetes Association introduced HbA1c test for diagnosing diabetes with a cut point of ≥6.5% in addition to criteria based on glucose levels.
Objective and hypotheses: The aim of this study was to evaluate the correlation between plasma glucose (fasting plasma glucose (FPG) and 2-h plasma glucose after an OGTT (2-h OGTT)) and HbA1c for diagnosing diabetes in Korean children.
Method: A total of 110 children without known diabetes completed an OGTT and HbA1c sampling. Diabetes was defined as a 2-h OGTT≥200 mg/dl, FPG≥126 mg/dl or HbA1c≥6.5%.
Results: Of 45 children with diabetes, 41 (91.1%) were diagnosis by HbA1c, 40 (88.9%) by 2-h OGTT, and 31 (68.9%) by FPG. Diagnostic sensitivity and specificity of diabetic criteria was higher in HbA1c than 2-h OGTT and FPG. Moderate agreement existed for HbA1c and FPG criteria (κ coefficient=0.714), and almost perfect agreement existed for HbA1c and 2-h OGTT criteria (κ coefficient=0.824) and HbA1c and FPG and/or 2-h OGTT criteria (κ coefficient=0.824) for diagnosing diabetes. FPG had the highest estimated area under the curve (AUC) among them. The AUC of HbA1c for identifying diabetic subjects according to FPG or 2-h OGTT criteria was 0.836 and 0.910. And, we found that an HbA1c level of 6.35% and FPG of 113 mg/dl have higher sensitivity and specificity, and an improved positive predictive value and negative predictive value than 6.5% and 126 mg/dl.
Conclusion: As a screening test for diagnosing diabetes, HbA1c is useful better than FPG and 2-h OGTT in children. But sensitivity and specificity of HbA1c≥6.5% for diagnosis of diabetes is low. So, children with HbA1c of 6.35 to 6.5% or FPG of 113 to 125 mg/dl should be tested OGTT to confirm diagnosis of diabetes.
20 - 22 Sep 2014
European Society for Paediatric Endocrinology