Validity and reliability of simple questions in assessing short- and long-term outcome in Norwegian stroke patients

The utility of simple questions for the assessment of stroke outcome in large-scale international studies has generally been approved, but their validity and reliability have not been evaluated in different cultures or at different intervals after a stroke. The study comprised 150 stroke patients who had been admitted consecutively to a stroke unit 6 weeks or 6 months earlier. Two weeks before the visit the patient received a postal questionnaire containing the simple 'dependency' question: 'In the last 2 weeks, did you require help from another person for everyday activities?' and the simple 'recovery' question: 'Do you feel that you have made a complete recovery from your stroke?'. The visit was performed by trained personnel unaware of the patient's or his carer's replies, and comprised the same 2 questions administered by the personnel, the Barthel ADL Index (BI) and the modified Rankin Scale (mRS). The patients' functional status was categorised as good or bad according to the chosen cutoff levels on BI and mRS. At 6 months the dependency question had an accuracy of 83 and 82% in identifying patients with good or bad outcome, defined as BI > or = 95 or < 95 and mRS < 3 or > or = 3, respectively, whereas the recovery question had an accuracy of 86% when compared with mRS = 0 or > 0. There was no difference in accuracy of the simple questions at 6 weeks compared with 6 months, and there was no clinically important difference between responses from patients and carers. The agreement between the responses to the questionnaire and the interview was good to moderate (kappa = 0.62 for the dependency question, and 0.55 for the recovery question). We conclude that the simple questions seem to be valid and reliable measures of stroke outcome when tested in Norwegian patients after 6 weeks or 6 months, which supports their continued use in large-scale multinational stroke studies at different intervals after stroke.