Utility-Weighted Modified Rankin Scale Scores for the Assessment of Stroke Outcome: Pooled Analysis of 20 000+ Patients

• Published in: Stroke (1970) 2020-08, Vol.51 (8), p.2411-2417
• Main Authors: Wang, Xia, Moullaali, Tom J., Li, Qiang, Berge, Eivind, Robinson, Thompson G., Lindley, Richard, Zheng, Danni, Delcourt, Candice, Arima, Hisatomi, Song, Lili, Chen, Xiaoying, Yang, Jie, Chalmers, John, Anderson, Craig S., Sandset, Else Charlotte
• Format: Article
• Language: English
• Subjects: Brain Ischemia - diagnosis; Brain Ischemia - psychology; Humans; Linear Models; Multicenter Studies as Topic - methods; Multicenter Studies as Topic - standards; Quality of Life - psychology; Randomized Controlled Trials as Topic - methods; Randomized Controlled Trials as Topic - standards; Stroke - diagnosis; Stroke - psychology; Surveys and Questionnaires - standards; Treatment Outcome
• ISSN: 0039-2499; 1524-4628; 1524-4628
• DOI: 10.1161/STROKEAHA.119.028523

BACKGROUND AND PURPOSE:Patient-centered care prioritizes patient beliefs and values towards wellbeing. We aimed to map functional status (modified Rankin Scale [mRS] scores) and health-related quality of life on the European Quality of Life 5-dimensional questionnaire (EQ-5D) to derive utility-weighted (UW) stroke outcome measures and test their statistical properties and construct validity. METHODS:UW-mRS scores were derived using linear regression, with mRS as a discrete ordinal explanatory response variable in 8 large international acute stroke trials. Linear regression models were used to validate UW-mRS scores by assessing differences in mean UW-mRS scores between the treatment groups of each trial. To explore the variability in EQ-5D between individual mRS categories, we generated receiver operator characteristic curves for EQ-5D to differentiate between sequential mRS categories and misclassification matrix to classify individual patients into a matched mRS category based on the closest UW-mRS value to their observed individual EQ-5D value. RESULTS:Among 22 946 acute stroke patients, derived UW-mRS across mRS scores 0 to 6 were 0.96, 0.83, 0.72, 0.54, 0.22, −0.18, and 0, respectively. Both UW-mRS and ordinal mRS scores captured divergent treatment effects across all 8 acute stroke trials. The sample sizes required to detect the treatment effects using UW-mRS scores as a continuous variable were almost half that required in trials for a binary cut point on the mRS. Area under receiver operator characteristic curves based on EQ-5D utility values varied from 0.66 to 0.81. Misclassification matrix showed moderate agreement between actual and matched mRS scores (kappa, 0.68 [95% CI, 0.67–0.68]). CONCLUSIONS:Medical strategies that target avoiding dependency may provide maximum benefit in terms of poststroke health-related quality of life. Despite variable differences with mRS scores, the UW-mRS provides efficiency gains as a smaller sample size is required to detect a treatment effect in acute stroke trials through use of continuous scores. REGISTRATION:URLhttps://www.clinicaltrials.gov; Unique identifiersNCT00226096, NCT00716079, NCT01422616, NCT02162017, NCT00120003, NCT02123875. URLhttp://ctri.nic.in; Unique identifierCTRI/2013/04/003557. URLhttps://www.isrctn.com; Unique identifierISRCTN89712435.