Validation of the Simplified Modified Rankin Scale Questionnaire

Abstract

Introduction: The modified Rankin scale (mRS) is the most common assessment tool for measuring overall functional outcome in stroke studies. The traditional way of using mRS face-to-face is time- and cost-consuming. The aim of this study was to test the validity of the Swedish translation of the simplified modified Rankin scale questionnaire (smRSq) as compared with the mRS assessed face-to-face 6 months after a stroke.

Methods: Within the ongoing EFFECTS trial, smRSq was sent out to 108 consecutive stroke patients 6 months after a stroke. The majority, 90% (97/108), of the patients answered the questionnaire; for the remaining 10%, it was answered by the next of kin. The patients were assessed by face-to-face mRS by 7 certified healthcare professionals at 4 Swedish stroke centres. The primary outcome was assessed by Cohen's kappa and weighted kappa.

Results: There was good agreement between postal smRSq, answered by the patients, and the mRS face-to-face; Cohen's kappa was 0.43 (CI 95% 0.31-0.55), weighted kappa was 0.64 (CI 95% 0.55-0.73), and Spearman rank correlation was 0.82 (p < 0.0001). In 55% (59/108), there was full agreement, and of the 49 patients not showing exact agreement, 44 patients differed by 1 grade and 5 patients had a difference of 2 grades.

Discussion/conclusion: Our results show good validity of the postal smRSq, answered by the patients, compared with the mRS carried out face-to-face at 6 months after a stroke. This result could help trialists in the future simplify study design and make multicentre trials and quality registers with a large number of patients more feasible and time-saving.

Keywords: Agreement; EFFECTS; Face-to-face assessment; Modified Rankin scale; Simplified modified Rankin scale questionnaire.