PURPOSE: Patient-reported health-related quality of life is a complementary healthcare outcome and important when assessing treatment efficacy. Using COSMIN methodological recommendations, this study evaluates the validity and reliability of a core heart disease-specific health-related quality of life questionnaire, the HeartQoL questionnaire (Danish version) in a sample of patients following heart valve surgery.
DESIGN: This project involved a cross-sectional validity study and a test-retest reliability study.
METHODS: Eligible patients completed the HeartQoL, the SF-36 health survey questionnaire, and the Hospital Anxiety and Depression Scale following heart valve surgery. Construct validity was tested using a priori hypotheses. Internal consistency reliability was assessed with Cronbach's alpha. An independent sample of patients participated in the test-retest study and reproducibility was determined with relative [intra-class correlation coefficient (ICC)] and absolute reliability [standard error of measurement (SEM) and smallest detectable change (SDC)].
RESULTS: Internal consistency was high with Cronbach's alpha ≥ 0.87. ICC was 0.86-0.92. SEM ranged from 0.17 to 0.26 points and SDC ranged from 0.5 to 0.7 points. Construct validity was confirmed with 87% of all a priori hypotheses for predicted variables.
CONCLUSIONS: The HeartQoL questionnaire demonstrates acceptable construct validity, internal consistency, and test-retest reproducibility in patients following heart valve surgery. Future studies should focus on assessing the responsiveness of the HeartQoL questionnaire over time and following heart valve surgery.