The development and preliminary validation of a Preference-Based Stroke Index (PBSI)

BACKGROUND: Health-related quality of life (HRQL) is a key issue in disabling conditions like stroke. Unfortunately, HRQL is often difficult to quantify in a comprehensive measure that can be used in cost analyses. Preference-based HRQL measures meet this challenge. To date, there are no existing preference-based HRQL measure for stroke that could be used as an outcome in clinical and economic studies of stroke. The aim of this study was to develop the first stroke-specific health index, the Preference-based Stroke Index (PBSI). METHODS: The PBSI includes 10 items; walking, climbing stairs, physical activities/sports, recreational activities, work, driving, speech, memory, coping and self-esteem. Each item has a 3-point response scale. Items known to be impacted by a stroke were selected. Scaling properties and preference-weights obtained from individuals with stroke and their caregivers were used to develop a cumulative score. RESULTS: Compared to the EQ-5D, the PBSI showed no ceiling effect in a high-functioning stroke population. Moderately high correlations were found between the physical function (r = 0.78), vitality (r = 0.67), social functioning (r = 0.64) scales of the SF-36 and the PBSI. The lowest correlation was with the role emotional scale of the SF-36 (r = 0.32). Our results indicated that the PBSI can differentiate patients by severity of stroke (p < 0.05) and level of functional independence (p < 0.0001). CONCLUSIONS: Content validity and preliminary evidence of construct validity has been demonstrated. Further work is needed to develop a multiattribute utility function to gather information on psychometric properties of the PBSI.