Glucose tolerance and cardiovascular mortality - Comparison of fasting and2-hour diagnostic criteria

Background: New diagnostic criteria for diabetes based on fasting blood glu cose (FBG) level were approved by the American Diabetes Association. The im pact of using FBG only has not been evaluated thoroughly. The fasting and t he 2-hour glucose (2h-BG) criteria were compared with regard to the predict ion of mortality. Methods: Existing baseline data on glucose level at fasting and 2 hours aft er a 75-g oral glucose tolerance test from 10 prospective European cohort s tudies including 15388 men and 7126 women aged 30 to 89 years, with a media n follow-up of 8.8 years, were analyzed. Hazards ratios for death from all causes, cardiovascular disease, coronary heart disease, and stroke were est imated. Results: Multivariate Cox regression analyses showed that the inclusion of FBG did not add significant information on the prediction of 2h-BG alone (P >.10 for various causes), whereas the addition of 2h-BG to FBG criteria sig nificantly improved the prediction (P<.001 for all causes and P<.005 for ca rdiovascular disease). In a model including FBG and 2h-BG simultaneously, h azards ratios (95% confidence intervals) in subjects with diabetes on 2h-BG were 1.73 (1.45-2.06) for all causes, 1.40 (1.02-1.92) for cardiovascular disease, 1.56 (1.03 2.36) for coronary heart disease, and 1.29 (0.66-2.54) for stroke mortality, compared with the normal 2h-BG group. Compared with t he normal FBG group, the corresponding hazards ratios in subjects with diab etes on FBG were 1.21(1.01-1.44), 1.20 (0.88-1.64), 1.09 (0.71-1.67), and 1 .64 (0.88-3.07), respectively. The largest number of excess deaths was obse rved in subjects who had impaired glucose tolerance but normal FBG levels. Conclusions: The 2h-BG is a better predictor of deaths from all causes and cardiovascular disease than is FBG.