Comparison of glucose tolerance categories according to World Health Organization and American Diabetes Association diagnostic criteria in a population-based study in Brazil

OBJECTIVE - To compare the prevalence of different categories of glucose tolerance in a Japanese-Brazilian population using World Health Organization (WHO) and American Diabetes Association (ADA) diagnostic criteria. RESEARCH DESIGN AND METHODS - The analyses were based on the data obtained from a study conducted in a representative sample of the Japanese-Brazilian population composed of 647 subjects (40-79 years) who were submitted to a 2-h oral glucose tolerance test. Prevalence of glucose tolerance categories and the level of agreement (kappa statistics) were obtained using WHO and ADA criteria. Cardiovascular risk profile of the subjects with different diagnostic categories were compared. RESULTS - Similar prevalences of diabetes were found considering both criteria (WHO, 20.3%; ADA, 19.2%). The prevalence of impaired glucose tolerance (IGT) by WHO criteria was 14.7%, contrasting with 7.4% of impaired fasting glucose (IFG) by ADA criteria. Subjects with discordant diagnostic categories by the criteria, considered at risk for diabetes (IGT/IFG), showed a worse metabolic profile than the concordant normal subjects. However, subjects with discordant diagnoses who had IGT or diabetes by WHO criteria but who were normal by ADA criteria exhibited a higher number of cardiovascular risk factors (higher blood pressure and triglyceride and low HDL cholesterol) than those who were discordant (IFG/diabetes) by ADA criteria but normal by WHO criteria. CONCLUSIONS - Although the number of diabetic subjects was similar between the criteria, those identified as being at risk for diabetes were quite distinct. Fewer subjects were classified as having IFG by ADA criteria than as having IGT by WHO criteria. Abnormal glucose tolerance based on WHO criteria seems to identify a worse cardiovascular profile than abnormal tolerance based on ADA criteria. Follow-up studies are necessary to know the prognostic significance of IFG to predict subsequent diabetes.