Reliability of the modified rankin scale: A systematic review

Abstract

Background and Purpose-: A perceived weakness of the modified Rankin Scale is potential for interobserver variability. We undertook a systematic review of modified Rankin Scale reliability studies. Methods-: Two researchers independently reviewed the literature. Crossdisciplinary electronic databases were interrogated using the following key words: Stroke* Cerebrovasc* Modified Rankin* Rankin Scale* Oxford Handicap* Observer variation*. Data were extracted according to prespecified criteria with decisions on inclusion by consensus. Results-: From 3461 titles, 10 studies (587 patients) were included. Reliability of modified Rankin Scale varied from weighted κ=0.95 to κ=0.25. Overall reliability of mRS was κ=0.46; weighted κ=0.90 (traditional modified Rankin Scale) and κ=0.62; weighted κ=0.87 (structured interview). Conclusion-: There remains uncertainty regarding modified Rankin Scale reliability. Interobserver studies closest in design to large-scale clinical trials demonstrate potentially significant interobserver variability. © 2009 American Heart Association, Inc.