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

Abstract

A1C > or =6.5% has been recently proposed as the defining criterion for diabetes. However, performance characteristics of this definition have not been described. 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)). Participants with A1C > or =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%. A1C > or =6.5% identifies fewer individuals than DM(1999WHO) or DM(FPG126). Studies are needed to determine that A1C > or =6.5% compromises neither blood pressure and lipid management in early diabetes nor the implementation of lifestyle interventions for diabetes prevention.