Objective: Diabetes mellitus type 2 (DM2) is a risk factor for coronary heart disease (CHD). While there is a clear correlation of fasting blood glucose (FBG) and 2 h post-challenge blood glucose values (2h-BG) with microvascular complications, the risk for CHD conferred by glucose dysregulation antecedent to DM2 is less clear. Therefore, we investigated associations of FBG and 2h-BG values with the prevalence of CHD assessed by coronary angiography as the most sensitive diagnostic tool.
Research design and methods: Coronary angiography was performed in 1394 patients without known DM. Capillary blood glucose was analyzed before and 2 h after an oral glucose tolerance test. Associations between FBG as well as 2h-BG levels and the risk for CHD were assessed by logistic regression analysis.
Results: 1064 (75%) of patients were diagnosed with CHD. 204 (15%) were diagnosed with so far unknown DM2, 274 (20%) with isolated impaired fasting glucose (IFG), 188 (13%) with isolated impaired glucose tolerance (IGT) and 282 (20%) with both, IGT and IFG. We found a continuous increase in the risk for CHD with fasting and post-challenge blood glucose values even in the subdiabetic range. This correlation did however not suggest clear cut-off values. The increase in risk for CHD reached statistical significance at FBG levels of > 120 mg/dl (Odds Ratio of 2.7 [1.3-5.6] and 2h-BG levels > 140 mg/dl (141-160 mg/dl OR 1.8 [1.1-2.9], which was however lost after adjusting for age, sex and BMI.
Conclusions: In our study population we found a continuous increased risk for CHD at fasting and 2h-BG levels in the sub-diabetic glucose range, but no clear cut-off values for cardiovascular risk.