Circ Cardiovasc Qual
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Circ Cardiovasc Qual · Dec 2019
Systematic Evaluation of the Robustness of the Evidence Supporting Current Guidelines on Myocardial Revascularization Using the Fragility Index.
RCTs (randomized controlled trials) are the preferred source of evidence to support professional societies' guidelines. The fragility index (FI), defined as the minimum number of patients whose status would need to switch from nonevent to event to render a statistically significant result nonsignificant, quantitatively estimates the robustness of RCT results. We evaluate RCTs supporting current guidelines on myocardial revascularization using the FI and FI minus number of patients lost to follow-up. ⋯ More than a quarter of RCTs that support current guidelines on myocardial revascularization have a FI of 3 or lower, and over 40% of trials reveal a FI that is lower than the number of patients lost to follow-up. These findings suggest that the robustness of the findings that support current myocardial revascularization guidelines is tenuous and vulnerable to change as new evidence from RCTs appears.
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Circ Cardiovasc Qual · Dec 2019
ReviewFragility Index in Cardiovascular Randomized Controlled Trials.
Efficacy of an intervention is commonly evaluated using P values, in addition to effect size measures such as absolute risk reduction, relative risk reduction, and numbers needed to treat. However, these measures are not always intuitive to clinicians. The fragility index (FI) is a more intuitive number that can facilitate interpretation but can only be used with binary outcomes. FI is the minimum number of patients who must be moved from the nonevent group to the event group to turn a significant result nonsignificant. In this retrospective analysis, we assessed the robustness of cardiovascular randomized controlled trials (RCTs), which report a positive (statistically significant) primary outcome by using the FI. ⋯ Considerable variations in FI were observed among cardiovascular trials, suggesting the need for careful interpretation of results, particularly when number of patients lost to follow-up exceeds FI.