Further validation of the Preference-Based Stroke Index three months after stroke

Objective: To estimate the construct validity of the Preference-Based Stroke Index and its value added over a generic measure, the EuroQol-5D-3L at three months after stroke. Design: This is a secondary analysis of an existing inception cohort. Pearson correlation coefficients were estimated to test construct validity and Generalized Estimating Equation analysis was conducted to compare the strength of the correlations of the Preference-Based Stroke Index and EuroQol-5D-3L with other measures. Setting: Community. Subjects: Participants (n = 488) with confirmed diagnosis of stroke hospitalized within 72 hours. Main measures: Health-related quality of life was measured using Preference-Based Stroke Index and EuroQol-5D-3L. For validation purposes, the Stroke Impact Scale, Short Form-36 V1, Walking Speed, Two-Minute Walk Test, Berg Balance Scale, and the Mini-Mental State Examination were used. The Barthel Index and Canadian Neurological Scale were used to define known groups. Results: Preference-Based Stroke Index correlated moderately with the EuroQol-5D-3L (r = 0.73), Walking Speed (r = 0.68), Two-Minute Walk Test (r = 0.73), and Berg Balance Scale (r = 0.70) and strongly with Stroke Impact Scale Activities of Daily Living (r = 0.80). Correlations were significantly higher for the Preference-Based Stroke Index than EuroQol-5D-3L. Participants with mild stroke had a higher mean Preference-Based Stroke Index score (77.9 +/- 20.6) than participants with severe stroke (62.8 +/- 20.3). Participants with functional independence had higher Preference-Based Stroke Index (85.7 +/- 11.9) than those dependent for activities of daily living (60.8 +/- 19.7). Conclusion: Preference-Based Stroke Index demonstrated significantly higher construct validity compared to the EuroQol-5D-3L at three months post stroke and can discriminate among known groups.