Utility of hemoglobin A1c for the identification of individuals with diabetes and prediabetes in a Chinese high risk population

Abstract Background. The aim of the study was to assess the utility of Hemoglobin A1c (HbA1c) to identify individuals with undiagnosed DM and prediabetes (preDM) in the high risk population of Chinese people. Methods. A total of 424 high risk individuals without known diabetes, who met at least three of the high risk factors for DM (hypertension, abnormal blood lipid, family history of DM and high BMI) were selected for this study, HbA1c, fasting plasma concentrations of glucose (FPG) and a 75 g oral glucose tolerance test (OGTT) were measured. The performance of HbA1c in relation to undiagnosed DM and preDM investigated through receiver operating characteristic (ROC) curves, the reference for DM and preDM, are according to the 2011 WHO-FPG/OGTT criteria and the appropriate cut-off points of HbA1c for DM and preDM were assessed. The properties of HbA1c diagnosing DM and preDM were also compared with that of the fasting plasma glucose (FPG). Results. It was shown that the AUC (area under the curve) of the ROC curve for HbA1c predicting undiagnosed DM was similar to that of FPG, and the cut-off point of HbA1c 6.2% was optimal for predicting DM, with a sensitivity of 66%, and a specificity of 91%. Furthermore, the cut-off point of HbA1c was 5.9% for preDM with a sensitivity of 70%, a specificity of 87%. Conclusion. Collectively, this study found that the measurement of HbA1c may be efficient to diagnosis undiagnosed both DM and preDM with the cut-off point of 6.2% and 5.9%, respectively.