The Combination of Fasting Plasma Glucose and Glycosylated Hemoglobin as a Predictor for Type 2 Diabetes in Korean Adults

BACKGROUNDThe oral glucose tolerance test (OGTT) for detection of diabetes is difficult to perform in clinical settings. The aim of this study is to evaluate the performance of a more practical detection test, combined fasting plasma glucose (FPG) and glycosylated hemoglobin (HbA1c), as a predictor of diabetes mellitus (DM) in a Korean sample. METHODS: We examined 2,045 (M = 1,276, mean age = 47.8 +/- 9.0 yrs) medical check-up program participants between January 2002 to December 2003. FPG, HbA1c and a number of other biochemical tests were performed at baseline and four after years after initial screening. Patients who originally presented with diabetes were excluded. The characteristics of newly-diagnosed DM patients and non-diabetic patients were compared. RESULTS: The incidence of newly diagnosed diabetes was 1.6% (32/2,045) after four years of follow up. The subjects in the DM group were older, had higher levels of SBP, DBP, FPG, HbA1c, triglyceride, HDL cholesterol, GGT and LDH (P < 0.05). In multivariate logistic regression analysis, FPG (odds ratio [OR] 1.124) and HbA1c (OR 4.794) were significantly correlated with onset of diabetes (P < 0.05). The interaction parameter between FPG and HbA1c was more than 1.0, indicating that the two effects are synergistic. The predictive cut-off values of HbA1c and FPG were 5.35% (area under curve [AUC] = 0.944) and 102.5 mg/dL (AUC = 0.930), respectively. CONCLUSION: The combination of HbA1c above 5.35% and FPG above 102.5 mg/dL predicted the onset of diabetes in a Korean sample. These results suggest that the combination of FPG and HbA1c may be useful for predicting progression to type 2 diabetes in east Asians.