Hierarchical Composite Outcomes and Win Ratio Methods in Cardiovascular Trials: A Review and Consequent Guidance

Abstract

The win ratio is a method for analyzing a hierarchical composite outcome. It has been most widely used in randomized clinical trials (RCTs) in cardiovascular disease. We performed a review of cardiovascular RCTs using the win ratio published between January 2022 and July 2024. The aims were to summarize current use and to provide examples to illustrate effective use and communication. We identified 36 eligible RCTs, mainly in heart failure and ischemic heart disease. Intervention was pharmaceutical in 26, a procedure in 7, and treatment strategy in 3 trials. When outcomes were analyzed with both conventional composite end points or hierarchical analysis, the conclusions tended to be similar. The win ratio was often used to combine evidence from event outcomes and quantitative measures together in a hierarchical composite, as was done in 23 RCTs. It was also used to create a clinically more relevant measure in RCTs by recognizing the clinical priorities among event outcomes. Selected example RCTs illustrate how the clarity of win ratio findings can be improved by (1) complementing the win ratio (a relative measure) with the win difference, (2) identifying which components of a hierarchical composite drive the overall results, and (3) clearly prespecifying the outcomes and win ratio analysis to be used. We conclude with a set of recommendations for future use of hierarchical composite outcomes and the win ratio. When used wisely, the win ratio is a valuable tool in the analysis of RCTs.