Comparison of Local and Centrally Adjudicated Modified Rankin Scale Scores in the MOST Trial

BACKGROUND: The modified Rankin Scale (mRS) is a key measure of functional outcomes in stroke trials. To minimize variability, structured tools like the Rankin Focused Assessment and central adjudication are recommended. This study compares local versus centrally adjudicated mRS scores in the MOST trial (Multi-Arm Optimization of Stroke Thrombolysis). METHODS: MOST was a phase 3, single-blind, randomized trial evaluating argatroban, eptifibatide, or placebo in addition to intravenous thrombolysis. The primary outcome, 90-day mRS score, was gathered through in-person video recordings by blinded local personnel. Recordings were sent to central adjudicators for final scoring. As in-person visits became limited due to SARS-CoV-2, remote interviews were allowed. We hypothesized that local mRS scores would be moderately associated with central scores. Fleiss-Cohen quadratic weighted κ statistics were used to determine the strength of agreement. RESULTS: Out of 514 participants, 378 had recorded visits available (121 in-person video, 157 remote video, 100 remote audio). Local assessors were blinded 96.8% of the time and 85.4% of visits used the Rankin Focused Assessment. Overall agreement between local and central mRS scores was excellent (weighted κ, 0.87 [95% CI, 0.83-0.90]). A nonsignificant decrease in strength of agreement was noted for those with a nonzero baseline mRS (mRS score=0, 0.87 [95% CI, 0.84-0.91] versus mRS score >0, 0.80 [95% CI, 0.68-0.91]). Trial conclusions were unchanged when utilizing the local mRS versus central adjudication. CONCLUSIONS: Local mRS scores demonstrated strong agreement with central scores across all assessment modes. With blinded end point assessments, central mRS adjudication in acute stroke trials may not be necessary.