Diabetes Diagnostic Criteria and Impaired Glycemic States: Evolving Evidence Base

In 1979 and 1980, two groups, the National Diabetes Data Group in the United States and the World Health Organization (WHO), published reports addressing diabetes diagnostic criteria.1,2 The two groups reached the same conclusions, and the criteria were eventually adopted throughout the world (Table 1). Before that time, criteria were variable and established by research groups and clinicians using their individual clinical experiences and limited data.

By the late 1970s, research on the natural history of diabetes had accumulated such that the criteria put forth by these two reports considered the entire world’s literature and were evidence-based. Impaired glucose tolerance (IGT) was also established and defined as a 2-hour 75-g oral glucose tolerance test (OGTT) result of 140–199 mg/dl. IGT is an abnormal metabolic state that falls short of diabetes but is associated with an elevated risk of developing diabetes. These criteria provided a means to uniformly track secular trends of diabetes as the epidemic …