Report of the Japan Diabetes Society's Committee on the Diagnostic Criteria for Diabetes Mellitus and Glucose Metabolism Disorder

—A New Category of Fasting Plasma Glucose Values:“high-normal”

Abstract

The Japan Diabetes Society established fasting plasma glucose (FPG) values<110 mg/dl as the normal range (Diabetes Research and Clinical Practice 55: 73, 2002). Recent epidemiological data in Japan show that subjects with FPG values of 100 to 109 mg/dl, which are in the normal range, develop diabetes at a higher rate than subjects with FPG values<100 mg/dl. Moreover, 25-40% of the subjects with FPG 100 to 109 mg/dl would be diagnosed as the borderline type or diabetic type on a 75 g oral glucose tolerance test (OGTT). In order not to overlook the risk that subjects in this group will develop diabetes and at the same time not to mislabel the 60-75% of them as having the borderline type, who would be found to have the normal type on an OGTT, the committee recommends that subjects with a FPG value of 100 to 109 mg/dl be classified as “high-normal” in the normal range in the definition of glucose metabolism disorder. It is recommended that subjects with a “high-normal” FPG value undergo a 75 g OGTT for diagnosis as normal-, borderline-, or diabetic-type. Until the 75 g OGTT is performed, such subjects should be followed up as having a “high-normal” FPG value and appropriate lifestyle modifications, including improvement of obesity should be implemented according to the condition of the individual subject.