Background: Health-related quality of life (HRQoL) is an important outcome indicator for chronic diseases. This study aimed to develop a new instrument for assessment of HRQoL in chronic heart failure (CHF) and evaluate its psychometric properties.
Methods: This study included two steps of conceptualization and item generation, and assessment of the psychometric properties of an instrument for measuring HRQoL in patients with CHF. A sample of 495 patients with confirmed diagnosis of heart failure participated in the study. In addition to content validity, exploratory and confirmatory factor analyses, concurrent validity, convergent validity, known groups comparison were performed to assess construct validity. Internal consistency, and stability were estimated by the Cronbach's alpha, the MacDonal's Omega, and intraclass correlation coefficients.
Results: The content validity of the developed chronic heart failure quality of life questionnaire was assessed by 10 experts. The exploratory factor analysis indicated a four-factor solution for the instrument containing 21 items that jointly accounted for 65.65% of variance observed. The confirmatory factor analysis confirmed the four factor solution with the following fit indexes (χ2/df = 2.214, CFI = 0.947, NFI = 0.91, TLI = 0.937, IFI = 0.947, GFI = 0.899, AGFI = 0.869, RMSEA = 0.063). However, at this stage one item was removed. The concurrent and convergent validity of the CHFQOLQ-20 were established using the Short Form Health Survey (SF-36), and the MacNew Heart Disease Quality of Life Questionnaire, respectively. The known-groups validity as assessed by using the New York Heart Association (NYHA) functional classification showed that the questionnaire discriminated well between patients who differed in functional classification. The internal consistency and test-retest reliability of the CHFQOLQ-20 were satisfactory, with a Cronbach's alpha and intraclass correlation coefficient (ICC) values of 0.93 and 0.84, respectively.
Conclusion: The results confirmed that CHFQOLQ-20 is a valid and reliable instrument for measuring quality of life (QoL) in patients with CHF. It is a short and easy-to-use instrument that is also capable of assessing the cognitive functioning, which has been overlooked in previous questionnaires.
Keywords: Chronic heart failure; Health-related quality of life; Iran; Patient-reported outcome measure; Reliability; Validity.
© 2023. The Author(s).