Assessment tools for functional independence and residual disability after stroke: Are they comparable?

Introduction/Background The aim of this study was to investigate the correlations between the modified Rankin Scale (mRS) grades and Korean versions of the MBI (K-MBI) scores in assessing the residual functional status of stroke survivors. Material and method The Korean versions of the MBI and mRS scales were administered to 5759 ischemic stroke patients at 3 months after onset of stroke. The sensitivity and specificity were calculated at all possible K-MBI score cutoffs for each mRS grade in order to obtain the optimally corresponding K-MBI scores and mRS grades. Receiver operator characteristic (ROC) curves and the area under the curve (AUC) was calculated. Results The K-MBI cutoff points with the highest sum of sensitivity and specificity were 100 (sensitivity 0.940; specificity 0.612), 98 (sensitivity 0.904; specificity 0.838), 94 (sensitivity 0.885; specificity 0.937), 78 (sensitivity 0.946; specificity, 0.973), and 55 (sensitivity 937; specificity 0.986) for mRS grades 0, 1, 2, 3, and 4, respectively. The AUC for the ROC curve was 0.791 for mRS grade 0, 0.919 for mRS grade 1, 0.970 for mRS grade 2, 0.0 for mRS grade 3, and 0.991 for mRS grade 4. Conclusion The K-MBI cutoff score ranges for representing mRS grades were variable. mRS grades 0, 1, and 2 had narrow K-MBI score ranges, while mRS grades 3, 4, and 5 showed broad K-MBI score ranges. mRS grade seemed to sensitively differentiate mild residual disability of stroke survivors, whereas K-MBI can provide more specific information of the functional status of stroke survivors with moderate to severe residual impairment.