[Clinical screening examination for impaired glucose tolerance: is it possible to diagnose impaired glucose tolerance without a 75g oral glucose tolerance test?].

It is well known that diabetes mellitus is one of the most crucial risk factors in the pathogenesis of atherosclerosis, including cardiovascular diseases (CVD). Considerable epidemiological and clinical studies, such as the Funagata study and the Diabetes Epidemiology Collaborative analysis of Diagnostic criteria in Europe (DECODE) study, have established that even a prediabetic state, including impaired glucose tolerance (IGT), is strongly associated with the occurrence of CVD. For the diagnosis of IGT, the 75g oral glucose tolerance test (75g OGTT) is required clinically, but the test takes at least 2 hours, at considerable cost. Therefore, for the prevention of atherosclerosis and subsequent CVD, another methods and/or beneficial parameters are anticipated to diagnose IGT without 75g OGTT. Recent studies have suggested that subjects beyond approximately 100 mg/dl fasting plasma glucose (FPG) might be classified into IGT by using receiver operating characteristic (ROC) analyses, and that the FPG 100 mg/dl is a suitable cut-off level between IGT and normal glucose tolerance (NGT). In contrast, although it is difficult to distinguish IGT from NGT by the HbAlc level alone, the combination of FPG with HbAlc is more beneficial for the diagnosis of IGT.