Psychometric analysis of the kansas city cardiomiopathy questionnaire-23 in a european population

Background People affected by heart failure (HF) often exhibit poor quality of life, which places a great deal of burden on the healthcare systems. The Kansas City Cardiomyopathy Questionnaire (KCCQ)-23 is one of the most widespread instruments to measure quality of life in this population. So far, its psychometric properties have been investigated by a broad array of research, but the overall findings reveal inconsistency of the factorial structure and lack of rigorous psychometric testing. Objective The aim of this study was to evaluate the psychometric properties of the KCCQ-23 in a European cohort of HF patients. Methods The data used for this study were collected for the MOTIVATE-HF study, which was a three-arm, multicenter, randomized controlled trial to evaluate the effect of motivational interviewing for improving self-care in HF. A group of 510 patients (median age 74 years, IQR=18, 58% males) completed the KCCQ-23 along with clinical and psychosocial measures. Factorial validity was established with confirmatory factor analysis (CFA); omega and model-based internal consistency indexes were computed to examine the internal consistency of the scale. Convergent validity was established by correlating the KCCQ-23 scores with several clinical and psychosocial measures. Measurement invariance testing was conducted within a multigroup framework across patients with preserved vs those with reduced ejection fraction. Results Two CFA solutions were tested, which confirmed the theoretical and empirical models postulated by the original author. The internal consistency coefficients for the latent dimensions were adequate (Omega range =0.77-0.93; internal consistency coefficient =0.89-96)- KCCQ-23 scores were found to be correlated with ejection fraction, NYHA levels, quality of life, self-care confidence, anxiety and depression, and symptom burden, supporting its convergent validity. Finally, the KCCQ-23 was invariant across ejection fraction levels, both in the theoretical and empirical factor solution. Conclusion Overall, this study provides for the first time evidence that the KCCQ-23 has satisfactory psychometric properties, promoting its use in clinical settings and research to investigate the quality of life in patients with HF.