Comparison of the Diamond-Forrester method and a new score to estimate the pretest probability of coronary disease before exercise testing.

OBJECTIVE: We compared the Diamond-Forrester (DF) tabular method to assess pretest probability of coronary artery disease to a new scoring method (NS).

METHODS: We evaluated 544 patients with suspected coronary disease who underwent both exercise electrocardiography and coronary angiography. The prevalence of any coronary artery disease (CAD) (>/=1 vessel with a >/=50% stenosis) within low, intermediate, and high pretest probability groups defined by the 2 methods was compared. The DF method used age, sex, and symptoms. The NS used those 3 factors plus 7 other risk factors.

RESULTS: Overall prevalence of CAD was 41%. We compared the respective prevalence of CAD within pretest probability groups. Low probability: DF 27% versus NS 17% (P <.03); intermediate probability: DF 42% versus NS 47%; high probability: DF 70% versus NS 72%. We evaluated results separately in men and women. In women, no significant differences were found. However, in men, a significant difference in the low probability group was found (DF 47% versus NS 22%; P <.03). When the 47 asymptomatic patients were removed from the analysis, there were no differences between the 2 methods. Men: low probability, DF 17% versus NS 21%; intermediate probability, DF 45% versus NS 49%; high probability, DF 67% versus NS 72%. Women: low probability, DF 17% versus NS 15%; intermediate probability, DF 38% versus NS 27%; high probability, DF 83% versus NS 70%.

CONCLUSION: In symptomatic patients, the accuracy of the 2 methods was the same. In asymptomatic patients, further evaluation in larger populations will be needed.