Use of the Win Ratio in Cardiovascular Trials

Abstract

Objectives

The purpose of this study was to compare the win ratio (WR) with the corresponding hazard ratios (HRs) and 1/HR.

Background

The primary outcome in many cardiovascular trials is a composite that includes nonfatal and fatal events. The time-to-first event analysis gives equal statistical weighting to each component event. The WR, which takes into account the clinical importance and timing of the outcomes, has been suggested as an alternative approach.

Methods

Cox proportional hazards models and WR.

Results

In the these trials (n = 16) the WR and HR differed only slightly. For example, in the PARADIGM-HF (sacubitril/valsartan vs. enalapril), the primary outcome of time to first heart failure hospitalization (HFH) or cardiovascular death (CVD) and use of the Cox model gave a 1/HR of 1.25 (95% confidence interval [CI]: 1.12 to 1. 41; z-score = 4.8). Using WR for testing this composite in the hierarchical order of CVD and HFH gave a WR of 1.27 (95% CI: 1.15 to 1.39; z-score = 4.7), reflecting an effect similar to that of sacubitril/valsartan therapy on CVD and HFH. In the DIG (digoxin vs. placebo) trial, the outcome of time-to-first HFH or CVD using Cox gave a 1/HR of 1.18 (95% CI: 1.10 to 1.27; z-score = 4.5). Using the WR for testing this composite in the hierarchical order of CVD and HFH gave a WR of 1.14 (95% CI: 1.05 to 1.20; z-score = 3.1), reflecting a larger effect of digoxin on HFH than on CVD. Several other trials and endpoints including patient-reported measurements were studied.

Conclusions

In 16 large cardiovascular outcome trials, HR and WR provided similar estimates of treatment effects. The WR allows prioritization of fatal outcomes and the hierarchical testing of broader composite endpoints including patient-reported outcomes. In this way, the WR allows for the incorporation of patient-centered and other outcomes, while prioritizing the competing risk of death and hospital admission.