Development of a stroke-specific quality of life scale

Abstract

Background and purpose: Clinical stroke trials are increasingly measuring patient-centered outcomes such as functional status and health-related quality of life (HRQOL). No stroke-specific HRQOL measure is currently available. This study presents the initial development of a valid, reliable, and responsive stroke-specific quality of life (SS-QOL) measure, for use in stroke trials.

Methods: Domains and items for the SS-QOL were developed from patient interviews. The SS-QOL, Short Form 36, Beck Depression Inventory, National Institutes of Health Stroke Scale, and Barthel Index were administered to patients 1 and 3 months after ischemic stroke. Items were eliminated with the use of standard psychometric criteria. Construct validity was assessed by comparing domain scores with similar domains of established measures. Domain responsiveness was assessed with standardized effect sizes.

Results: All 12 domains of the SS-QOL were unidimensional. In the final 49-item scale, all domains demonstrated excellent internal reliability (Cronbach's alpha values for each domain >/=0.73). Most domains were moderately correlated with similar domains of established outcome measures (r2 range, 0.3 to 0.5). Most domains were responsive to change (standardized effect sizes >0.4). One- and 3-month SS-QOL scores were associated with patients' self-report of HRQOL compared with before their stroke (P<0.001).

Conclusions: The SS-QOL measures HRQOL, its primary underlying construct, in stroke patients. Preliminary results regarding the reliability, validity, and responsiveness of the SS-QOL are encouraging. Further studies in diverse stroke populations are needed.