Impaired glucose tolerance, impaired fasting glucose and cardiovascular risk.

To the Editor: Tamita et al reported that abnormal glucose tolerance in patients with acute myocardial infarction (AMI) is a major risk factor for future cardiovascular events and might critically distinguish high-risk individuals.1 The cardiovascular event-free survival rate in the impaired glucose tolerance (IGT) group and the group with newly diagnosed diabetes were 73% and 67%, respectively, at 5-year follow up. They combined these 2 groups as the abnormal glucose tolerance group and the event-free survival rate in the combined group was 70%, which was significantly lower than the rate (87%) in the normal glucose tolerance group. They pointed out the critical importance of oral glucose tolerance tests after AMI, because in their study, 81% of patients with newly-diagnosed abnormal glucose tolerance showed normal fasting plasma glucose concentrations defined as <110mg/dl. However, the p-values of the hazard ratio for abnormal glucose tolerance and fasting plasma glucose were 0.0068 and 0.001, respectively, in their univariate Cox regression analysis.1 Recently, the American Diabetes Association revised the cut point of impaired fasting glucose (IFG) as 100mg/dl2 and the International Diabetes Federation3 and the American Heart Association4 adopted this cut point. Therefore, they should evaluate not only IGT but also old and revised IFG as risk factors for future cardiovascular events as done by Kanaya et al.5 I deeply appreciate if they would also study C-reactive protein (CRP) as a risk factor for future cardiovascular events as suggested by Matsushita et al in their cross-sectional study. 6 The optimal cut point of CRP might be 0.65mg/L.7,8