Development of a Barthel Index based on dyspnea for patients with respiratory diseases

Background: As Barthel Index (BI) quantifies motor impairment but not breathlessness, the use of only this index could underestimate disability in chronic respiratory disease (CRD). To our knowledge, no study evaluates both motor and respiratory disability in CRD during activities of daily living (ADLs) simultaneously and with a unique tool. The objective of this study was to propose for patients with CRD an additional tool for dyspnea assessment during ADLs based on BI items named Barthel Index dyspnea. Methods: Comprehensibility, reliability, internal consistency, validity, responsiveness, and ability to differentiate between disease groups were assessed on 219 subjects through an observational study performed in an in-hospital rehabilitation setting. Results: Good comprehensibility, high reliability (interrater intraclass correlation coefficient was 0.93 [95% confidence interval 0.892-0.964] and test-retest intraclass correlation coefficient was 0.99 [95% confidence interval 0.983-0.994]), good internal consistency (Cronbach's alpha 0.89), strong concurrent validity with 6 minute walking distance (Pearson r=-0.538, P<0.001) and Medical Research Council (Spearman r(S)=0.70, P<0.001), good responsiveness after rehabilitation (P<0.001), and good appropriateness of the index were found evidencing patients with different dyspnea severity. Divergent validity showed weak correlation (Pearson r=-0.38) comparing Barthel Index dyspnea and BI. Conclusion: The BI based on dyspnea perception proved to be reliable, sensitive, and adequate as a tool for measuring the level of dyspnea perceived in performing basic daily living activities. A unique instrument simultaneously administered may provide a global assessment of disability during ADLs incorporating both motor and respiratory aspects.