Utility-Weighted Analysis of the Modified Rankin Scale: An Updated Review of Methods, Challenges, and Future Directions.

Abstract

The utility-weighted approach to analyzing the modified Rankin Scale (mRS) is increasingly being utilized in acute stroke clinical trials. This analytic approach assigns a patient-centered utility weight-the desirability or value of a health state to patients-to each level of the mRS. The utility-weighted-mRS analysis converts the mRS from a scale reflecting only the rank order of functional outcome after stroke into one that quantifies the value of each poststroke mRS health state from patients' perspectives. The ability of the utility-weighted-mRS analysis to capture the unequal difference in patient health-related quality of life between each level of the mRS makes it an appealing patient-centered end point for acute stroke clinical trials. However, several concerns have historically raised skepticism regarding its value as a trial end point. Unfamiliarity with how utility weights are derived and used poses challenges to its use for shared decision-making between patients and clinicians. There are valid concerns that social, geographic, and demographic factors that differ between countries influence the mRS utility weights, so that use of uniform weights across all settings mildly reduces the precision of utility quantification, particularly in multinational stroke clinical trials. This narrative review aims to provide the clinical and research stroke community with a practical overview of key methodology in the utility-weighted-mRS analysis to aid in its interpretation, considers the advantages and challenges of using the utility-weighted-mRS analysis, and suggests future areas of study.