The win ratio: A novel approach to define and analyze postoperative composite outcomes to reflect patient and clinician priorities.

BACKGROUND

The "win ratio" (WR) is a novel statistical technique that hierarchically weighs various postoperative outcomes (eg, mortality weighted more than complications) into a composite metric to define an overall benefit or "win." We sought to use the WR to assess the impact of social vulnerability on the likelihood of achieving a "win" after hepatopancreatic surgery.

METHODS

Individuals who underwent an elective hepatopancreatic procedure between 2013 and 2017 were identified using the Medicare database, which was merged with the Center for Disease Control and Prevention's Social Vulnerability Index. The win ratio was defined based on a hierarchy of postoperative outcomes: 90-day mortality, perioperative complications, 90-day readmissions, and length of stay. Patients matched based on procedure type, race, sex, age, and Charlson Comorbidity Index score were compared and assessed relative to win ratio.

RESULTS

Among 32,557 Medicare beneficiaries who underwent hepatectomy (n = 11,621, 35.7%) or pancreatectomy (n = 20,936, 64.3%), 16,846 (51.7%) patients were male with median age of 72 years (interquartile range 68-77) and median Charlson Comorbidity Index of 3 (interquartile range 2-8), and a small subset of patients were a racial/ethnic minority (n = 3,759, 11.6%). Adverse events associated with lack of a postoperative optimal outcome included 90-day mortality (n = 2,222, 6.8%), postoperative complication (n = 8,029, 24.7%), readmission (n = 6,349, 19.5%), and length of stay (median: 7 days, interquartile range 5-11). Overall, the patients from low Social Vulnerability Index areas were more likely to "win" with a textbook outcome (win ratio 1.07, 95% confidence interval 1.01-1.12) compared with patients from high social vulnerability counties; in contrast, there was no difference in the win ratio among patients living in average versus high Social Vulnerability Index (win ratio 1.04, 95% confidence interval 0.98-1.10). In assessing surgeon volume, patients who had a liver or pancreas procedure performed by a high-volume surgeon had a higher win ratio versus patients who were treated by a low-volume surgeon (win ratio 1.21, 95% confidence interval 1.16-1.25). In contrast, there was no difference in the win ratio (win ratio 1.01, 95% confidence interval 0.97-1.06) among patients relative to teaching hospital status.

CONCLUSION

Using a novel statistical approach, the win ratio ranked outcomes to create a composite measure to assess a postoperative "win." The WR demonstrated that social vulnerability was an important driver in explaining disparate postoperative outcomes.