Simple exercise test score versus cardiac stress test for the prediction of coronary artery disease in patients with type 2 diabetes

Abstract

Type 2 diabetes markedly increases the risk of coronary heart disease (CHD), and screening for CHD is suggested by the guidelines. The aim of the study was to compare the diagnostic usefulness of the simple exercise test score, incorporating the clinical data and cardiac stress test results, with the standard stress test in patients with type 2 diabetes. A total of 62 consecutive patients (aged 65.4 ±8.5 years; 32 men) with type 2 diabetes and clinical symptoms suggesting CHD underwent a stress test followed by coronary angiography. The simple score was calculated for all patients. Significant coronary stenosis was observed in 41 patients (66.1%). Stress test results were positive in 36 patients (58.1%). The mean simple score was high (65.5 ±14.3 points). A positive linear relationship was observed between the score and the prevalence of CHD (R2 = 0.19; P <0.001) as well as its severity (R² = 0.23; P <0.001). The area under the receiver-operating characteristic curve for the simple score was 0.74 (95% confidence interval [CI], 0.62-0.86). At the original cut-off value of 60 points, the score had a similar prognostic value to that of the standard stress test. However, in a multivariate analysis, only the simple score (odds ratio [OR], 1.46; 95% CI, 1.11-1.94; P <0.01 for an increase in the score by 1 point) and male sex (OR, 1.57; 95% CI, 1.24-1.98; P <0.001) remained independent predictors of CHD. In patients with type 2 diabetes, the simple score correlated with the prevalence and severity of CHD. However, the cut-off value of 60 points was inadequate in the population of diabetic patients with high risk of CHD. The simple score used instead of or together with the stress test was a better predictor of CHD than the stress test alone.