Can Admission and Fasting Glucose Reliably Identify Undiagnosed Diabetes in Patients With Acute Coronary Syndrome?

OBJECTIVE—Our objectives were to determine the prevalence of previously undiagnosed abnormal glucose tolerance, i.e., diabetes and impaired glucose tolerance (IGT) in patients with acute coronary syndrome and to assess the utility of admission and fasting glucose in identifying diabetes in these patients. RESEARCH DESIGN AND METHODS—Glycemic status was characterized on the basis of admission plasma glucose (APG), fasting plasma glucose (FPG), and an oral glucose tolerance test (OGTT) in 140 patients admitted to the hospital with acute coronary syndrome, who were not known to have diabetes (mean ± SD age 67.3 ± 13.4 years; 79% men). OGTTs were performed on days 5–7 after admission. RESULTS—The prevalences of diabetes and IGT were 27 and 39%, respectively, according to OGTT criteria. Receiver operating characteristic curves showed that the area under the curve for diagnosing diabetes was 0.83 (P < 0.001) for FPG, 0.79 (P < 0.001) for APG, and 0.84 (P < 0.001) for FPG and APG applied in combination. A FPG cutoff ≥5.6 mmol/l (100 mg/dl) and/or APG ≥7.8 mmol/l (140 mg/dl) yielded a sensitivity of 89.5% and a positive predictive value of 43.6% for detecting diabetes. CONCLUSIONS—A high prevalence of abnormal glucose tolerance was seen in patients with acute coronary syndrome. The combination of FPG ≥5.6 mmol/l (100 mg/dl) and/or APG ≥7.8 mmol/l (140 mg/dl) was highly sensitive for identifying diabetes. Although weakly specific, this simple algorithm could offer a practical initial screening tool at the acute setting in the high-risk population with acute coronary syndrome.