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

Abstract

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/m(2), age >or=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.