Prognostic value of a negative stress echocardiographic study in diabetic patients

Background Diabetic patients have increased cardiovascular morbidity and mortality. We compared the long-term prognostic value of a negative, nonischemic stress echocardiogram in patients with and without diabetes. Methods Two hundred thirty-six consecutive subjects who had stress echocardiography and who were negative for inducible ischemia were included in the study. Baseline cardiac risk factors and cardiac events (cardiac death, nonfatal myocardial infarction, and coronary revascularization) were identified. Results Follow-up was obtained in 233 subjects for a mean duration of 25 months. There were 144 nondiabetic and 89 diabetic patients. At baseline, the diabetic group had a significantly higher incidence of hypertension, hyperlipidemia, and history of coronary artery disease but had a lower incidence of smoking (P < .05). Diabetic patients had a significantly higher incidence of cardiac events (19% vs 9.7%, P = .03) and worse event-free survival (P = .03). There were more nonfatal myocardial infarctions in the diabetic group (6.7% vs 1.4%, P < .05) and a trend toward a higher proportion of hard events (myocardial infarction and cardiac death) in diabetic patients (12.4% vs 5.6%, P = .11). The hard event rate per year of follow-up was 2.7% in nondiabetic and 6.0% in diabetic patients. In diabetic patients, a history of coronary artery disease was the only predictor of cardiac events (R = 0.18, P < .05). Conclusion Compared with nondiabetic patients, diabetic patients with negative stress echocardiograms are at greater risk for cardiac events. This appears to be due to a higher prevalence of established coronary disease in diabetic patients.