Performance characteristics of the new definition of diabetes: The insulin resistance atherosclerosis study

OBJECTIVE - A1C≥6.5% has been recently proposed as the defining criterion for diabetes. However, performance characteristics of this definition have not been described. RESEARCH DESIGN AND METHODS - In the Insulin Resistance Atherosclerosis Study, we compared new to previous definitions of diabetes: 1999 World Health Organization (DM_1999WHO) and 2003 American Diabetes Association based on fasting glucose alone (DM_FPG126). RESULTS - Participants with A1C≥6.5%,DM_1999WHO, and DM_FPG126 were 44 (5.2%), 132 (15.4%), and 61 (7.1%), respectively. In individuals with DM_1999WHO, mean, median, and interquartile range of A1C were 6.3, 5.9, and 5.5- 6.6%, respectively; in individuals with DM_FPG126 , mean, median, and interquartile range of A1C were 7.0, 6.6, and 6.0 -7.1%. CONCLUSIONS - A1C ≥6.5% identifies fewer individuals than DM _1999WHO or DM_FPG126 . Studies are needed to determine that A1C ≥6.5% compromises neither blood pressure and lipid management in early diabetes nor the implementation of lifestyle interventions for diabetes prevention.