Prevalence, predictors, and consequences of unrecognized diabetes mellitus in 3266 patients scheduled for coronary angiography

Background Previous population-based studies have reported a proportion of undiagnosed diabetes in the range between 25% and 50%. However, data on undiagnosed diabetes in a high-risk population, such as patients scheduled for coronary angiography, are lacking. Therefore, we sought to determine prevalence, predictors, and consequences of unrecognized diabetes in patients scheduled for coronary angiography. Methods This analysis involved 3266 patients scheduled for coronary angiography who have been enrolled in the Ludwigshafen Risk and Cardiovascular Health study. Results Five hundred fifty-six patients (17.0%) had known diabetes. Another 486 patients with previously unrecognized diabetes (17.9%) were diagnosed in the remaining 2710 presumed nondiabetic subjects. Therefore, 486 (46.6%) of a total of 1042 patients with diabetes were previously undiagnosed, raising the diabetic proportion of enrolled patients to 31.9%. In half of the newly diagnosed patients with diabetes, the disease was detectable only by use of glucose challenge. Independent predictors of unrecognized type 2 diabetes were C-reactive protein >5 mg/L, arterial hypertension, body mass index >30 kg/m2, age ≥65 years, and a positive family history of diabetes. Compared with nondiabetic subjects, patients with unrecognized type 2 diabetes showed a significantly increased risk for coronary artery disease (odds ration [OR] 1.7, 95% CI 1.3-2.3) and multivessel disease (OR 1.4, 95% CI 1.1-1.8), and a borderline association with myocardial infarction (OR 1.2, 95% CI 1.0-1.5). Oral glucose challenge was not superior to fasting glucose in predicting this increased cardiovascular risk. Conclusion In half of the patients scheduled for coronary angiography, diabetes was previously unrecognized. In a high-risk population of patients scheduled for coronary angiography, screening for diabetes should be performed routinely to initiate timely preventive efforts. (Am Heart J 2003;145:285-91.)