Relationship of Barthel Index and its Short Form with the Modified Rankin Scale in acute stroke patients

Background: Modified Rankin Scale and Barthel Index are the most common scales for assessing stroke outcomes in clinical practice and trials. Concordance between the Barthel Index scores and the modified Rankin Scale grades is important to define favorable outcome in clinical practice and stroke trials consistently. The purpose of this study was to examine the relationship between the scores of Barthel Index and 3-item Barthel Index Short Form with the modified Rankin Scale grades of acute stroke patients. Methods: Barthel Index, Barthel Index Short Form scores and modified Rankin Scale grades of 516 stroke patients were obtained from a follow-up study of the Longshi Scale in China. A study showed that the assignment of modified Rankin Scale grades to stroke patients was prone to misclassification. Therefore, the recorded modified Rankin Scale grades were compared with the Barthel Index scores of each patient to produce the adjusted modified Rankin Scale grades. Receiver operating characteristics curve analyses were performed to determine the optimal cutoff scores, respective sensitivities and specificities of Barthel Index and Barthel Index Short Form with the corresponding adjusted modified Rankin Scale grades <= 1, <= 2 and <= 3. Findings: About 44% of the recorded modified Rankin Scale grades of patients required adjustment. The optimal cutoff scores were >= 100 (sensitivity 100%; specificity 95.3%), >= 100 (sensitivity 98.1%; specificity 100%) and >= 75 (sensitivity 93.8%; specificity, 91.9%) for the Barthel Index and >= 40 (sensitivity 100%; specificity 78.9%), >= 40 (sensitivity 98.1%; specificity 82.8%), and >= 35 (sensitivity 99.3%; specificity, 91.6%) for the Barthel Index Short Form corresponding to the adjusted modified Rankin Scale grade <= 1, <= 2, and <= 3 respectively. The areas under the receiver operating characteristic curves were nearly all above 0.9. Conclusions: The optimal cutoff scores of Barthel Index and Barthel Index Short Form corresponding to the modified Rankin Scale grades <= 1, <= 2 and <= 3 were recommended to be >= 100 and >= 40, >= 100 and >= 40, and >= 75 and >= 35 respectively for determining the favorable and unfavorable outcome of stroke patients within three months of onset in clinical practice and trials.