We thank Dr Bob Bernstein for his insightful comments1 on our recent publication in Canadian Family Physician.2 However, there has been a misunderstanding in the interpretation of our work detailing the predictive validity of several available tests for the investigation of chest pain.
The values presented in Table 1 of our article are aggregate data reported in the literature and not calculated figures from any one study. Dr Bernstein presented a series of 2 × 2 tables in his letter to demonstrate that the sensitivity and specificity reported for a variety of investigative tests were not concordant with positive and negative predictive values for the identification of coronary artery disease (CAD). In our article, we did not claim that either set of values can be used to mathematically derive the other—rather, we reported on the range of published diagnostic accuracy measures (including sensitivity, specificity, and likelihood ratios) based on the most robust published studies to date.
Dr Bernstein cited a pretest likelihood for CAD of 10% and 50% for low- and intermediate-risk groups, respectively.1 However, these estimates depend on the specific patient population evaluated and the risk scoring systems used. We agree with Dr Bernstein that clinical judgment is critical and that patients with low pretest likelihood of CAD typically do not require any noninvasive testing.
Footnotes
Competing interests
None declared
- Copyright © the College of Family Physicians of Canada
