Composite outcomes and making sense of the ‘win ratio’

23/02/24

Introduction

Global improvements in healthcare provision over time has resulted in event rates in clinical trials, such as mortality and hospitalisations, to decline in frequency. Adequately powering these studies to detect meaningful differences between treatment arms (if a true difference exists) therefore mandates recruiting larger sample sizes at the expense of time, labour, and costs. Using composite as opposed to single endpoints has been popularised to overcome this barrier. The development of hierarchical endpoints and the method of the ‘win ratio’ has increasingly gained favour as a more sensitive way to evaluate composite outcomes. We discuss the nuances of composite endpoint analysis, how the win ratio works, and review examples of recent clinical trials using this methodology.