Postprandial hyperglycemia has emerged as a new glycometabolic condition associated with an excessive risk for coronary artery disease. We therefore attempted to evaluate the frequency of postchallenge hyperglycemia in patients with acute coronary syndrome (ACS) who were not previously diagnosed to have diabetes and did not have a fasting glucose concentration of > or =7 mmol/l or an HbA(1c) level >6.0%. We further correlated the presence of postchallenge hyperglycemia with the extent of coronary atherosclerosis. In all, 134 consecutive ACS patients who met the above inclusion criteria were studied. An oral glucose tolerance test was performed before discharge. The mean age, fasting glucose, and HbA(1c) were 60 years, 5.15 mmol/l, and 5.4%, respectively. Among ACS patients, impaired glucose tolerance (IGT) and diabetes were found in 50 (37%) and 13 patients (10%), respectively. The homeostasis model assessment for insulin resistance did not differ substantially among the normal glucose tolerance (NGT), IGT, and diabetic groups. Insulinogenic index, however, was lower and the number of stenosed vessels higher in diabetic patients compared with NGT patients. Postchallenge hyperglycemia, caused primarily by impaired initial insulin secretion, is commonly found in Japanese ACS patients who have not been previously diagnosed with diabetes, and this phenomenon is considered to be associated with advanced coronary atherosclerosis. Therefore, the present study strongly supports the notion that oral glucose tolerance test assessment of postchallenge hyperglycemia is essential to identify any previously undiagnosed diabetes cases among Japanese ACS patients.
