Improving modified Rankin Scale assessment with a simplified questionnaire.

BACKGROUND AND PURPOSE The modified Rankin Scale (mRS) is a popular primary stroke outcome measure, but its usefulness is limited by suboptimal reliability (inter-rater agreement). METHODS We developed and tested the reliability of a simplified mRS questionnaire (smRSq) in 50 patients after stroke seen in outpatient clinics. Randomly chosen paired raters administered the smRSq within 20 minutes of each other and the ratings were blinded until the end of this study. RESULTS Agreement among the raters was 78%, the kappa statistic was 0.72 (95% CI, 0.58-0.86), and the weighted kappa(w) statistic taking into account the extent of disagreement was 0.82 (95% CI, 0.72-0.92). The average time to administer the smRSq was 1.67 minutes. CONCLUSIONS The smRSq appears to have very good reliability that is similar to that of a structured interview mRS and is considerably less time-consuming.