The value of glycated hemoglobin versus fasting plasma glucose for the screening of diabetes mellitus

Objective To explore the optimal cut-off point of the glycosylated hemoglobin(HbA_1c) versus fasting plasma glucose(FPG) for screening diabetes(DM),and to validate the current HbA_1c diagnostic criteria from large-scale epidemiological survey.Methods A total of 1330 non-diabetic subjects who participated in health examination in Nanjing were included.All subjects underwent standardized breakfast and HbA_1c measurement.Receiver operating characteristic(ROC) curve analysis was used to examine the sensitivity and specificity of FPG and HbA_1c for diagosing diabetes,which was defined by the standard from WHO in 1999.Results DM prevalence was 6.8%.Based on the ROC curve,the optimal cut-point of FPG related to the OGTT-diagnostic criteria for diabetes was 6.1 mmol/L which was associated with a sensitivity and specificity of 81.30%and 96.3%respectively.The optimal cut-point of HbAlc related to diabetes diagnosis by OGTT was 6.1%,which was associated with a sensitivity and specificity of 83.5%and 88.8%respectively.If the proposed use of HbA_1c≥6.5%of ADA as a diagnostic criteria for DM was adopted,the sensitivity and specificity were 59.3%and 97.4%. If the newly proposed HbA_1c≥6.3%as a diagnostic criteria of DM for the Chinese population was adopted,the sensitivity and specificity were 71.4%and 94.7%.The screening model using FPG≥6.1mmol/L or HbAlc≥6.1%had sensitivities of 92.3%for detecting undiagnosed diabetes. Conclusions Compared with HbA_1c in screening DM,FPG has a slightly higher diagnostic value.The simultaneous measurement of FPG and HbAlc might be a more sensitive and specific screening tool for identifying high-risk individuals for diabetes at an early stage.