PURPOSE: Both the presence of diabetes mellitus (DM) and the presence and severity of coronary artery disease (CAD) predict recurrent major adverse cardiovascular events (MACE). The purpose of our study was to examine the correlation between DM, coronary angiographic findings and the risk of MACE among patients with established CAD.
METHODS: We prospectively followed 347 males with CAD undergoing coronary angiography for 4 years. The combined endpoint was the occurence of MACE, including myocardial infarction, unstable angina, stroke, coronary revascularization and death. We used logistic regression and calculated odds ratios (OR) and the area under the receiver-operator characteristic curve (AU-ROC)for each logistic regression model to directly compare their predictive ability.
RESULTS: Univariate predictors of MACE included DM (OR=2.36;95%CI=1.49-3.74;p<0.001), left ventricular ejection fraction (OR per 10% increase=0.77;95%CI=0.66-0.90;p=0.001), congestive heart failure (OR=2.33;95%CI=1.30-4.17;p=0.004), peripheral vascular disease (OR=2.10;95%CI=1.23-3.57;p=0.006) and serum creatinine (OR per mg/dL increase=1.32;95%CI=1.02-1.71;p=0.03). DM was the strongest predictor of MACE (AU-ROC=0.60). The number of coronary territories involved with hemodynamically significant CAD tended to predict MACE (OR per vessel involved=1.24;95%CI=0.99-1.55;p=0.05). DM remained the strongest predictor of MACE in multivariate models. The best model constructed with multiple angiography-related variables (number of vessels with significant CAD, history of previous CABG, need for CABG or percutaneous coronary intervention from findings during index angiography, and presence left main stenosis) had an AU-ROC of 0.58. This was inferior to the AU-ROC for the model containing DM alone (0.60).
CONCLUSION: DM is a stronger predictor of recurrent MACE than the angiographic severity of CAD. DM is associated with continuous exposure to a pro-atherogenic milieu and extracardiac atherosclerotic disease, explaining its strong ability to predict cardiovascular events beyond the angiographic presence or severity of CAD.
CLINICAL IMPLICATIONS: DM a much stronger risk factor for future cardiovascular events than coronary angiographic findings at any given time. Diabetics should be regarded as high-risk patients even when the coronary angiogram is normal or reveals mild abnormalities.
DISCLOSURE: Julio Chirinos, None.