Validity of the modified Rankin Scale in patients with aneurysmal subarachnoid hemorrhage: a randomized study

Abstract

Abstract Purpose The modified Rankin Scale (mRS), a clinician-reported outcome measure of global disability, has never been validated in patients with aneurysmal subarachnoid hemorrhage (aSAH). The aims of this study are to assess: 1) convergent validity of the mRS; 2) responsiveness of the mRS; and 3) the distribution of mRS scores across patient reported outcome measures (PROMs). Methods This is a prospective, randomized, multicenter study. The mRS was scored by a physician for all patients; subsequently for one half by structured interview and the other half by self-assessment. All patients completed EuroQoL 5D-5L, RAND-36, Stroke Specific Quality of Life scale (SS-QoL) and Global Perceived Effect (GPE). Convergent validity and responsiveness were assessed by testing hypotheses. Results In total, 149 patients were included for analysis. The correlation of the mRS with EQ-5D-5L was r = -0.546, with RAND-36 physical and mental component score being r = -0.439 resp. r = -0.574, and with SS-QoL r = -0.671. Three out of four hypotheses for convergent validity were met. The mRS assessed through structured interview has higher correlation with the mental component score than with the physical component score of RAND-36. Improvement on GPE was indicated by 83% of patients; the mean change score of these patients on the mRS was − 0.08 (SD 0.915). None of the hypotheses for responsiveness were met. Conclusion The results show that the mRS generally correlates with other instruments as expected, but it lacks responsiveness. A structured interview of the mRS is best for detecting disabling neuropsychological complaints. Registration URL: https://trialsearch.who.int; Unique identifier: NL7859, Date of first administration: 08-07-2019