The clinical meaning of Rankin 'handicap' grades after stroke.

Abstract

The Rankin Scale is a frequently used handicap index in stroke outcome research. However, relatively little is known about its validity. The purpose of this study was to investigate the clinical meaning of Rankin grades by identifying the functional health aspects that contribute to Rankin scores. We studied 438 patients 6 months after stroke. Data were collected on the following functional health indicators: alertness, communication, independence, disability in activities of daily living, mobility, instrumental disability, social interaction, and recreation. Disability in activities of daily living was assessed with the Barthel Index, whereas the other indicators were measured with subscales of the Sickness Impact Profile. The association between functional health and Rankin Scale was expressed in terms of relative frequencies and Somers' D statistic. Linear regression analysis (after ordinal transformation) was used to identify the significant health factors that explain Rankin scores. Mobility, disability in daily and instrumental activities, and living arrangements showed a stronger association with Rankin scores (Somers' D range, 0.60 to 0.74) than cognitive and social functioning (Somers' D range, 0.34 to 0.47). Disability in activities of daily living turned out to be the most important explanatory factor of Rankin scores (R2 = 67%). The Rankin Scale is not a pure handicap measure but should be viewed as a global functional health index with a strong accent on physical disability. The index is useful as a simple and time-efficient outcome measure in largescale multicenter trials. It is argued that at present there is no clear need to assess handicap as the primary outcome in medically oriented stroke intervention studies.