DIAGNOSTIC-ACCURACY OF PREDICTING CORONARY-ARTERY DISEASE-RELATED TO PATIENTS CHARACTERISTICS

Patients' demographic and clinical characteristics may affect diagnost ic accuracy of cardiologists. We asked a group of experienced cardiolo gists from three institutions to estimate the pretest probability of c oronary artery disease in 257 patients referred for diagnostic coronar y angiography and with no history of previous myocardial infarction no r valvular heart disease. Physicians pretest estimates were compared w ith the diagnostic findings of coronary angiography. We tested the inf luence of five variables on the accuracy of the pretest estimates: age , sex, chest pain characteristics, rest electrocardiogram and electroc ardiographic exercise test result. Cardiologists tended to overestimat e the presence of coronary artery disease and this tendency was partic ularly remarkable in the group of patients showing a negative exercise test. Pretest diagnostic accuracy was 0.72 when the test result was n egative and 0.85 when the test result was positive (95% confidence int erval of the difference 0.03 to 0.23; p < 0.001). The diagnosis of cor onary artery disease was also more accurate for male than for female p atients (0.81 vs 0.70; 95% confidence interval of the difference 0.02 to 0.21; p < 0.02). Characteristics of chest pain, age and rest electr ocardiogram did not affect the level of pretest diagnostic accuracy. C ardiologists should be cognizant of correctly interpreting a negative exercise test and the clinical data of female patients; in both cases, they should move circumspect of the diagnosis of coronary artery dise ase.