Reliability (inter-rater agreement) of the Barthel Index for assessment of stroke survivors: systematic review and meta-analysis.

BACKGROUND AND PURPOSE The Barthel Index (BI) is a 10-item measure of activities of daily living which is frequently used in clinical practice and as a trial outcome measure in stroke. We sought to describe the reliability (interobserver variability) of standard BI in stroke cohorts using systematic review and meta-analysis of published studies. METHODS Two assessors independently searched various multidisciplinary electronic databases from inception to April 2012 inclusive. Inclusion criteria comprised: original research, human stroke participants, and inter-rater reliability data on equivalent methods of BI administration. Manuscripts were reviewed against prespecified inclusion criteria. Primary outcome for meta-analysis was reliability, measured by weighted κ (κw). RESULTS From 20 210 titles, 306 abstracts were reviewed, 12 studies met inclusion criteria, and 10 were included in meta-analysis (n=543 participants; range of participants in studies, 7-21). There was substantial clinical heterogeneity with respect to method of BI application; population studied and assessors. Two papers were graded high quality. Overall interobserver reliability of standard administration of the BI was excellent (κw, 0.93; 95% confidence interval, 0.90-0.96 random effects modeling). CONCLUSIONS The BI has excellent inter-rater reliability for standard administration after stroke. However, included studies were modest in size, with clinical heterogeneity and variable methodological quality. Despite these limitations, standard BI seems an appropriate outcome measure for stroke trials and practice.