Development and validation of NEWSQOL, the Newcastle Stroke-Specific Quality of Life Measure

BACKGROUND: A review of stroke-specific quality of life (QOL) measures indicated little evidence of their validity/reliability. PURPOSE: To describe the development/validation of a new measure - the Newcastle Stroke-Specific Quality of Life Measure (NEWSQOL). METHODS: Phase I: qualitative interviews (28 stroke patients) determined QOL issues for inclusion in the measure. Initial items/response categories were pre-tested (30 patients). Administration of the NEWSQOL in the item reduction stage (100 patients) identified poorly performing items and factor analysis showed likely domains. Internal consistency was examined. Phase II: NEWSQOL and comparator measures were administered (106 patients) to examine validity/test-retest reliability. RESULTS: Phase I: 140 items were identified for initial inclusion. Qualitative pre-testing led to an extensive revision. Item reduction resulted in a final measure of 56 items in 11 domains (feelings, activities of daily living/self-care, cognition, mobility, emotion, sleep, interpersonal relationships, communication, pain/sensation, vision, fatigue; Cronbach's alpha = 0.71-0.90). Phase II: NEWSQOL domain scores, except cognition, were moderately/highly correlated (0.45-0.76) with relevant comparator measures. NEWSQOL domains feelings, communication and cognition low/moderately correlated with Barthel Index scores (-0.49 to -0.28), as predicted. Test-retest reliability was high (intraclass correlation coefficient range 0.78-0.92). CONCLUSIONS: NEWSQOL is an acceptable, patient-derived, interviewer-administered, stroke-specific QOL measure with evidence of reliability and validity, making it a promising instrument for assessing QOL after stroke. Involvement of relevant patients in determining the content and format considerably enhances confidence in its validity.