The aim of this study was to compare the recent HbA1c diagnostic criteria proposed by both the International Expert Committee (IEC) and the American Diabetes Association (ADA) for screening for diabetes with the oral glucose tolerance test (OGTT) which is considered the “gold standard” for identification of diabetes. For that purpose, data from three datasets were analyzed: the Screening for Impaired Glucose Tolerance (SIGT) study (n=1,581 subjects), the National Health and Nutrition Examination Survey (NHANES) III (n=2,014) and NHANES 2005-2006 (n=1,111). Analyses revealed that the IEC and ADA HbA1c diagnostic criteria have limitations for use as a screening test. Using OGTT results, 5.8% of the combined study subjects had new diabetes and 36% had pre-diabetes. However, when compared with an OGTT, HbA1c testing resulted in more normal diagnoses and fewer high-risk and diabetes diagnoses than with both the IEC and ADA criteria. Results also showed that HbA1c criteria resulted in more false-positive and fewer false-negative results in Blacks compared with Whites. These results suggest that HbA1c diagnostic criteria are insensitive and racially discrepant for screening and may incorrectly identify high-risk individuals.
Documentation centre