A postal version of the Barthel Index

The Barthel Index is the best known and most popular activities of daily living (ADL) scale. Many studies have confirmed its validity and it has been validated for many different methods of administration. These include direct observation, interview of patient carer or nurse and telephone. The aim of this study was to devise and test the reliability of a self-completed postal version of the Barthel Index for use in surveys and outcome studies. The items were changed into multiple choice questions, taking into account the published guidelines and knowledge of common areas of confusion when administering the Barthel by interview. The test retest reliability over two weeks of the resulting questionnaire was evaluated using a consecutive series of 21 patients from a stroke register, who had responded without prompting to a postal survey six months after stroke. All the items had κ statistics indicating at least moderate reliability, the toilet and mobility items being the worst. The mean difference in total scores was -0.5 out of 20, standard deviation 2.1. The 95% limits of agreement were -4.6 to 3.6, corresponding to a change in dependence of up to two ADL items. This study demonstrates that the postal self-report questionnaire version of the Barthel is reliable and practical. Further studies are needed to establish its validity in comparison with interview administration.