Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

OBJECTIVE: To compare how 3 common representations (ordinal vs dichotomized as 0-1/2-6 or 0-2/3-6) of the modified Rankin Scale (mRS)-a commonly used trial outcome measure-relate to long-term outcomes, and quantify trial ineligibility rates based on premorbid mRS. METHODS: In consecutive patients with ischemic stroke in a population-based, prospective, cohort study (Oxford Vascular Study; 2002-2014), we related 3-month mRS to 1-year and 5-year disability and death (logistic regressions), and health/social care costs (generalized linear model), adjusted for age/sex, and compared goodness-of-fit values (C statistic, mean absolute error). We also calculated the proportion of patients in whom premorbid mRS score >1 or >2 would result in exclusion from trials using dichotomous analysis. RESULTS: Among 1,607 patients, the ordinal mRS was more strongly related to 5-year mortality than both the 0-1/2-6 and 0-2/3-6 dichotomies (all p < 0.0001). Results were similar for 5-year disability, and 5-year care costs were also best captured by the ordinal model (change in mean absolute error vs age/sex: -$3,059 for ordinal, -$2,805 for 0-2/3-6, -$1,647 for 0-1/2-6). Two hundred forty-four (17.1%) 3-month survivors had premorbid mRS score >2 and 434 (30.5%) had mRS score >1; both proportions increased with female sex, socioeconomic deprivation, and age (all p < 0.0001). CONCLUSION: The ordinal form of the 3-month mRS relates better to long-term outcomes and costs in survivors of ischemic stroke than either dichotomy. This finding favors using ordinal approaches in trials analyzing the mRS. Exclusion of patients with higher premorbid disability by use of dichotomous primary outcomes will also result in unrepresentative samples.

Original publication

DOI

10.1212/WNL.0000000000006554

Type

Journal article

Journal

Neurology

Publication Date

20/11/2018

Volume

91

Pages

e1951 - e1960