Exploring the reliability of the modified Rankin Scale

Quinn, T.J. , Dawson, J. , Walters, M. and Lees, K.R. (2009) Exploring the reliability of the modified Rankin Scale. Stroke, 40(3), pp. 762-766. (doi:10.1161/STROKEAHA.108.522516)

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Publisher's URL: http://dx.doi.org/10.1161/STROKEAHA.108.522516

Abstract

<p><b>Background and Purpose:</b> The modified Rankin Scale (mRS) is the most prevalent outcome measure in stroke trials. Use of the mRS may be hampered by variability in grading. Previous estimates of the properties of the mRS have used diverse methodologies and may not apply to contemporary trial populations. We used a mock clinical trial design to explore inter- and intraobserver variability of the mRS.</p> <p><b>Methods:</b> Consenting patients with stroke attending for outpatient review had the mRS performed by 2 independent assessors with pairs of assessors selected from a team of 3 research nurses and 4 stroke physicians. Before formal assessment, interviewers estimated disability based only on initial patient observation. Each patient was then randomized to undergo the mRS using standard assessment or a prespecified structured interview. The second interviewer in the pair reassessed the patient using the same method blinded to the colleague’s score. For each patient assessed, one rater was randomly assigned to video record their interview. After 3 months, this interviewer reviewed and regraded their original video assessment.</p> <p><b>Results:</b> Across 100 paired assessments, interobserver agreement was moderate (k=0.57). Intraobserver variability was good (k=0.72) but less than would be expected from previous literature. Forty-nine assessments were performed using the structured interview approach with no significant difference between structured and standard mRS. Researchers were unable to reliably predict mRS from initial limited patient assessment (k=0.16).</p> <p><b>Conclusions:</b> Despite availability of training and structured interview, there remains substantial interobserver variability in mRS grades awarded even by experienced researchers. Additional methods to improve mRS reliability are required.</p>

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Lees, Professor Kennedy and Quinn, Dr Terence and Dawson, Professor Jesse and Walters, Professor Matthew
Authors: Quinn, T.J., Dawson, J., Walters, M., and Lees, K.R.
College/School:College of Medical Veterinary and Life Sciences > Institute of Cardiovascular and Medical Sciences
Journal Name:Stroke
Publisher:American Heart Association
ISSN:0039-2499
ISSN (Online):1524-4628
Published Online:08 January 2009
Copyright Holders:Copyright © 2009 American Heart Association
First Published:First published in Stroke 40(3):762-766
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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