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

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, and subsequently by structured interview for half of the patients and by self-assessment for the other half. All patients completed EuroQoL 5D-5L, RAND-36, Stroke Specific Quality of Life scale (SS-QoL) and Global Perceived Effect (GPE) questionnaires. Convergent validity and responsiveness were assessed by testing hypotheses. RESULTS: In total, 149 patients with aSAH were included for analysis. The correlation of the mRS with EQ-5D-5L was r = -?0.546, while with RAND-36 physical and mental component scores the correlation was r = -?0.439and r = -?0.574 respectively, and with SS-QoL it was r = -?0.671. Three out of four hypotheses for convergent validity were met. The mRS assessed through structured interviews was more highly correlated with the mental component score than with the physical component score of RAND-36. Improvement in terms of 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.