Use of the Barthel index and modified Rankin scale in acute stroke trials

Abstract

Background and purpose: The Barthel Index (BI) and the Modified Rankin Scale (MRS) are commonly used scales that measure disability or dependence in activities of daily living in stroke victims. The objective of this study was to investigate how these scales were used and interpreted in acute stroke trials.

Methods: We identified from MEDLINE the major efficacy trials with neuroprotective drugs, thrombolytic drugs, and anticoagulants in acute ischemic stroke published between January 1995 and December 1998. We selected those trials that used the BI and/or MRS as outcome parameters.

Results: Fifteen trials fulfilling the inclusion criteria were identified. The BI was used in 13 and the MRS in 8. In 4 trials mean and median scores of the BI were used, and in 1 trial median scores of the MRS were compared. Primary end points included the BI in 7, the MRS in 6, and both the BI and MRS in 3. With regard to the BI, a variety of sum scores between 50 and 95 were used as cutoff scores to define favorable outcome. Favorable outcome on the MRS was defined as either </=1 or </=2.

Conclusions: Among the efficacy trials in acute stroke, we found remarkable differences in the choice of primary end points and in the definition of favorable outcome on both the BI and MRS. This lack of consensus strongly hinders the design, interpretation, and comparison of acute stroke trials. In general, it may be easier to define poor outcome instead of favorable outcome. Poor outcome could be defined if any of the following end points are reached: death, institutionalization due to stroke, MRS >3, or BI <60.