New insights into validity, reliability, and measurement invariance of the Kansas City Cardiomyopathy Questionnaire 23

Background: People affected by heart failure (HF) often exhibit a poor health status, which places a great deal of burden on the healthcare systems. The Kansas City Cardiomyopathy Questionnaire (KCCQ) 23 is the most used tool to measure the health status in this population; however, its psychometric properties have not been thoroughly established.Objective: To evaluate the psychometric properties of the KCCQ-23 in a European cohort of HF patients.Methods: 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 clinical and psychosocial measures. Measurement invariance tests across those with preserved vs reduced ejection fraction were conducted within a multigroup framework.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 evidence of satisfactory psychometric properties of the KCCQ-23, promoting its use in clinical settings and research fields.