Utility-weighted modified Rankin Scale: Still too crude to be a truly patient-centric primary outcome measure?

Abstract

Background: The utility-weighted modified Rankin Scale (UW-mRS) is an outcome measure recently proposed to improve statistical efficiency and interpretability of the mRS. Statistical properties of the UW-mRS have been well investigated, but construct validity has yet to be established. Aims: To investigate the construct validity of the UW-mRS as a primary outcome measure by assessing variability in utility values within and between mRS categories, over time post-stroke, and by different derivation methods. Methods: UW-mRS was derived using assessment of quality of life (AQoL-4D) and mRS scores at 3 and 12 months (n = 2030) from a large randomized controlled trial, A Very Early Rehabilitation..