A comparison of the Barthel Index and the OPCS disability instrument used to measure outcome after acute stroke.

The Barthel Index has been widely adopted as a measure of disability. The Office of Population Censuses and Surveys (OPCS) disability instrument was developed to provide a comprehensive measure of disability for use in the 1985 survey of disability among adults. Both measures were used on 150 patients surviving 1 year from a consecutive cohort of 246 admissions to hospital with acute stroke. The Barthel Index when summed across categories (as is commonly done), correlated reasonably well with the OPCS disability instrument [-0.73 (p < 0.001) 95% CI 0.64 to 0.80] despite its reliance on arbitrary weights and the omission of categories for communication, vision, hearing and intellectual disability. The broader scope of the OPCS instrument explained most of the floor and ceiling effects seen with the Barthel Index. The Barthel Index continues to have a useful role in stroke rehabilitation when used as a checklist for rehabilitation goals set by clinicians, as a predictor of long-term outcome and as an overall measure of disability or activities of daily living in descriptive studies, randomized controlled trials and audit. However, its floor and ceiling effects may lead to an underestimation of patients' and carers' problems in up to a third of patients. The OPCS instrument may prove to be a more useful outcome measure in randomized controlled trials and audits by virtue of its comprehensive nature.