Psychometric Testing of the Kansas City Cardiomyopathy Questionnaire 12 in A European Population

Introduction The Kansas City Cardiomyopathy Questionnaire (KCCQ) is one of the most widely used instruments for measuring health-related quality of life of patients with heart failure (HF). However, its 12-item version (KCCQ-12) was not sufficiently tested in European populations, and its invariance in patients with reduced, midrange, and preserved ejection fraction has never been assessed. Aims The purpose of this study is to examine the validity and reliability of the KCCQ-12 in a large cohort of Italian patients with HF and assess its measurement invariance across levels of ejection fraction. Methods A total of 510 patients (mean age = 72 years, 58% males) completed the KCCQ-12 alongside other measures of depression, anxiety, quality of life, and HF symptom burden. Construct validity was assessed by means of a confirmatory factor analysis and by testing the association of the KCCQ-12 scores with clinical parameters (ie, ejection fraction and mortality at 12 months) as well as measures of anxiety, depression, symptom burden, and general quality of life. Multigroup confirmatory factor analysis was implemented to investigate invariance properties across those with reduced, midrange, and preserved ejection fraction. Omega and model-based internal consistency coefficients were computed to investigate internal consistency reliability. Results The confirmatory factor analysis specified according to the original 4-factor model (ie, physical and social limitations, symptom frequency, and quality of life) yielded satisfactory fit indices (root mean square error of approximation = 0.053, comparative fit index = 0.98). Moderate-to-high correlations were found between the KCCQ-12 and the mental and physical component scores of the Short Form 12, as well as other conceptually related constructs, indicating adequate facets of construct validity. Multigroup confirmatory factor analysis tested across patients with different ejection fraction groups, established that the KCCQ-12 was invariant at the partial scalar level. Omega and model-based internal consistency coefficients were adequate, ranging from 0.75 to 0.90 for the subscales, and 0.94 for the whole scale, confirming strong internal consistency reliability. Conclusions The KCCQ-12 demonstrated satisfactory psychometric properties in our European sample of patients with HF, providing evidence to support its use in practice and further research.