The fasting plasma glucose cut-point predicting a diabetic 2-h OGTT glucose level depends on the phenotype

Abstract

To assess the use of fasting plasma glucose (FPG) alone for the screening of diabetes as defined by a 2-h plasma glucose (2-h PG) > or =11.1 mmol/l following a 75-g oral glucose tolerance test, we collated the results from 17512 subjects aged 30-89 years without a previous history of diabetes from 12 general population-based Asian studies. The performance of FPG corresponding to the 2-h PG > or =11.1 mmol/l was characterized. The prevalence of diabetes was 4.0% by the FPG criteria only and 6.0% by the 2-h PG criteria only. The FPG value of 7.0 mmol/l gave a sensitivity for diabetes as defined by a 2-h PG > or =11.1 mmol/l of 46% and specificity of 99%. The FPG associated with a 2-h PG > or =11.1 mmol/l with optimal sensitivity and specificity was 5.8 mmol/l (sensitivity 79%, specificity 85%). The optimal FPG cut-point was affected by gender, age, body mass index and the presence of hypertension, and the resulting sensitivity and specificity corresponding to each optimal cut-point changed. The FPG was a specific but insensitive screening test for diabetes defined by 2-h PG > or =11.1 mmol/l. There seems to be ethnic differences with respect to optimal FPG cut-point, and different screening strategies may be necessary in different parts of the world.