Predicting the Course of Unstable Angina

Excerpt

To the Editors: The recent article by Marmur and colleagues (1) suggests that quantitative tomographic exercise thallium scintigraphy is of value in identifying patients who are at risk for subsequent adverse events after medical stabilization and hospital care for unstable angina. We have several concerns about study design and data analysis that may invalidate the authors' conclusions.

First, the methods used to follow the two study groups were not equal. The patients in the "adverse outcome" group clearly were sicker and were receiving more medication at baseline. Undoubtedly, this group received greater medical attention after hospitalization than did the "no