Background and purpose: The Barthel Index for assessing activities of daily living (ADL) was developed particularly for young stroke patients, but it now has a wider application in the geriatric assessment profile. This study tests the validity of the Barthel Index by self-report in the old-old (> or = 75 years). If more than 10% of the studied population assessed themselves incorrectly (> or = 15-point discrepancy), the test may have limitations. We set out to try to quantify and explain this discrepancy.
Methods: During a 3-month period, we tested 126 old-old patients, both geriatric medical inpatients and subjects from the community, in a cross-sectional study. Using the Barthel Index, their functional status was assessed by self-report and by observation of performance. A measure of the magnitude of discrepancy between the two methods (discrepancy score) was calculated as the difference between the self-report and performance total scores.
Results: Comparing the self-report with actual ADL performance scores, the mean score for self-report was higher (90 vs 88). There was a low Kappa score in all areas of the scale (range 0.103-0.398). Twenty of the 126 patients (15.9%) scored 15 or more points in the discrepancy score. By running a multiple linear regression, we were able to explain only 21% of the variance in the discrepancy score (R2 = .21). Significant explanatory variables were the presence of cognitive impairment, source of patients from acute geriatric ward, and age (very old > or = 85 years).
Conclusion: For the purpose of this study, use of the Barthel Index by self-reporting was found to have its limitations in the old-old (> or = 75 years), particularly with regard to the very old (> or = 85 years) medical geriatric inpatients. Therefore, we suggest that the older people may have to be assessed by the rehabilitation services using a performance-based measure or a different self-report test for documenting their activities of daily living, bearing in mind that self-reported and performance-based measures capture physical abilities differently.