Use of Win Statistics to Analyze Outcomes in the DAPA-HF and DELIVER Trials

Abstract

BackgroundThe primary end point in most heart failure (HF) trials is a composite of time to a first worsening HF event or cardiovascular death. Prevention of recurrent events and improvements in symptoms/quality of life are also important for patients but are usually analyzed separately. Win statistics can integrate all these outcomes into a single composite end point, which is analyzed in hierarchical order, reflecting the clinical importance of each component.MethodsThe Dapagliflozin and Prevention of Adverse Outcomes in Heart Failure (DAPA-HF, n=4744) and Dapagliflozin Evaluation to Improve the Lives of Patients with Preserved Ejection Fraction Heart Failure (DELIVER, n=6263) trials enrolled patients with New York Heart Association class II, III, or IV HF, elevated natriuretic peptides, and either an ejection fraction of 40% or less (DAPA-HF) or greater than 40% and left atrial enlargement/left ventricular hypertrophy (DELIVER). We examined the effects of dapagliflozin compared with placebo on a hierarchical composite outcome, including cardiovascular death, total (first and recurrent) HF hospitalizations, total urgent HF visits, and improvement/deterioration in Kansas City Cardiomyopathy Questionnaire total symptom score (KCCQ-TSS; range from 0 to 100, with a higher score indicating fewer symptoms and physical limitations) at 8 months.ResultsFor this composite outcome, the win ratio was 1.30 (95% confidence interval [CI], 1.23 to 1.36) in the pooled cohort, 1.33 (95% CI, 1.23 to 1.43) in the DAPA-HF trial, and 1.27 (95% CI, 1.18 to 1.36) in the DELIVER trial. Win odds and net benefit in overall patients were 1.19 (95% CI, 1.14 to 1.24) and 8.7% (95% CI, 6.6 to 10.9%), respectively. In the overall pooled cohort, the majority of wins and losses were accounted for by KCCQ-TSS; 52.4% were settled by the KCCQ-TSS tier in the pooled cohort.ConclusionsIn both the DAPA-HF and DELIVER trials, dapagliflozin led to a significant improvement in composite outcomes that incorporated patient-reported outcomes along with total HF events, as well as cardiovascular deaths. These analyses provided a comprehensive presentation of win statistics and illustrated the utility and flexibility of win statistics in describing the effects of dapagliflozin in two recent clinical trials in patients with HF. (Funded by British Heart Foundation Centre of Research Excellence and others; clinical trial registration numbers, NCT03036124 and NCT03619213.)