The Fragility of Some Clinical Trials

We depend on randomized trials to support clinical practice and often focus intently on the overall result. However, a reader may reasonably ask about the robustness of the result. In fact, there is a metric, the fragility index, to assess robustness. The index is defined as the minimum number of patients whose outcome would need to switch (from event to nonevent) to change a statistically significant result into a nonsignificant one (a lower index indicates a less robust result). Researchers have now assessed the fragility index in the randomized trials supporting current guidelines addressing myocardial revascularization from the American College of Cardiology and American Heart Association (ACC/AHA) and the European Society of Cardiology…