BACKGROUND
The criteria for the diagnosis of diabetes mellitus have been modified by the American Diabetes Association (ADA) in 1997. The ADA proposed that the diagnosis of diabetes be defined by a fasting plasma glucose (FPG) of 7.0 mmol/L. Disagreement has been reported between criteria based on FPG and postchallenge 2-h plasma glucose (2-h PG). The aim of the present study is to assess the FPG criteria as the diagnostic screening test for diabetes in Korean middle-aged adults in comparison to the 2-h PG criteria. METHODS: Randomly selected 1,731 subjects (679 men and 1,052 women) aged 40~70 years (mean age: 58.4 +/- 7.89 years) without previously diagnosed diabetes completed 75 g oral glucose tolerance test (OGTT). We assessed the prevalence of diabetes mellitus and the level of agreement (kappa statistics) according to the different diagnostic glucose categories. RESULTS: The frequency of newly diagnosed diabetes was 2.7% (n = 51) using the FPG criteria only; 6.4% (n = 120) using the 2-h PG criteria only; and 6.9% (n = 130) using concentrations of > or = 7.0 mmol/L for FPG or > or = 11.1 mmol/L for 2-h PG. Of the 120 subjects with diabetes by the 2-h PG criteria, 65.8% (n = 79) were not diagnosed with diabetes according to FPG concentration. The level of agreement between two diagnostic criteria was low (kappa = 0.268). The receiver operating characterstic (ROC) curve analysis determined FPG of 5.6 mmol/L to yield optimal sensitivity and specificity corresponding to 2-h PG 11.1 mmol/L. CONCLUSION: The findings in this study demonstrate that the discordance between the FPG and 2-h PG criteria in the diagnosis of diabetes in Korean middle-aged adults is large. We suggest that IFG group (FPG 5.6~6.9 mmol/L) were performed 75 g OGTT for diagnosing diabetes mellitus in Korean middle-aged adults.