Plasma glucose and prediction of microvascular disease and mortality - Evaluation of 1997 American Diabetes Association and 1999 World Health Organization criteria for diagnosis of diabetes

OBJECTIVE - The 1997 American Diabetes Association (ADA) and 1999 World Health Organization (WHO) criteria for diabetes and hyperglycemia were evaluated and compared with respect to prediction of microvascular and macrovascular disease and mortality. RESEARCH DESIGN AND METHODS - The prevalence of retinopathy and nephropathy at baseline and during the subsequent 10 years and mortality rates were examined in relation to baseline fasting plasma glucose (FPG) and 2-h postload plasma glucose (2-h PG) among 5,023 Pima Indian adults and in relation to the cut points defined by the ADA and WHO criteria. RESULTS - The frequencies of retinopathy and nephropathy were directly related to baseline FPG and 2-h PG with approximate thresholds near or below the current diagnostic criteria for diabetes (FPG greater than or equal to 7.0 and 2-h PG greater than or equal to 11.1 mmol/l). The rates of retinopathy were 4.7% in impaired fasting glucose (IFG) and 20.9% in diabetes by ADA criteria; 1.6% for impaired glucose tolerance (IGT) and 19.7% for diabetes by 1985 WHO criteria; and 1.2% for IGT and 19.2% for diabetes by the 1999 WHO criteria. Mortality rates from cardiovascular-renal-related diseases were higher in diabetic individuals (FPG greater than or equal to 7.0 or 2-h PG greater than or equal to 11.1 mmol/l) than in those with normal FPG and 2-h PG but were not elevated in those with IFG or IGT. CONCLUSIONS - Retinopathy and nephropathy were directly related to higher FPG or 2-h PG. FPG, which identifies those at high risk of microvascular disease and mortality, can be used to predict these outcomes and to diagnose diabetes when oral glucose tolerance testing is not practical.