Measuring Quality of Life in Patients with Ventricular Assist Device - Psychometric Evaluation of the German Version of the Disease Specific QoLVAD-Questionnaire

Abstract

<h3>Purpose</h3> Due to an increasing number of Ventricular assist device (VAD)-patients, patient-reported outcome measures assessing health-related quality of life (HRQoL) become important. No valid and reliable German instrument for VAD patients has been established. <h3>Methods</h3> In a nation-wide, multi-center, cross-sectional study, 393 participants completed the German translation of the Quality of Life with a Ventricular Assist Device (QoLVAD) questionnaire. The QoLVAD developed by Sandau et al. does assess five VAD specific QoL domains: physical, emotional, social, cognitive and spirituality. Psychometric evaluation was performed to test the applicability for clinical practice. Item and confirmatory factor analysis (CFA) were conducted. For convergent validity the Kansas City Cardiomyopathy Questionnaire (KCCQ) and the Patient Health Questionnaire-9 (PHQ-9) were used. <h3>Results</h3> Overall, 85.8 % of the sample was male; mean age 58.3 (range 18-85). The majority followed a bridge to transplant therapy (33.1 %) and were on VAD support for less than a year (38.9 %). The QoLVAD showed good item difficulty (P_total=0.67) and the majority of items had moderate to high discriminatory power (r_it<0.3). Most Items demonstrated significant associations with total HRQoL and the five domains. Besides root mean square error of approximation (=0.07), indices of model fit were moderate (comparative/Tucker-Lewis fit indices=0.66/0.65; standardized root mean square residual=0.11). Seven items with low factor loadings (<0.30) were identified. Each QoLVAD domain demonstrated significant correlations with established measures supporting convergent validity (Table 1). <h3>Conclusion</h3> Findings indicate a promising standardized measure of QoL for patients on ongoing VAD support. Item reduction may increase model fit and psychometric quality of the instrument to improve its applicability in clinical practice.