HRQoL is an important outcome measure for clinical research. However, the majority of the available questionnaires are not patient-driven, and to the best of the authors’ knowledge, CHFQOLQ-20 is the first patient-driven questionnaire for assessment of HRQoL in CHF. The CHFQOLQ-20 includes important domains of HRQoL known by patients. Factor analysis extracted four factors of (I) physical functioning, (II) cognitive functioning, (III) general health, and (IV) mental health. These subscales all were confirmed by the CFA.
The first underlying factor identified by factor analysis had a clear reflection of physical functions, and had 10 items. Thus, it was labeled as physical functioning according to ICF. This subscale is the main core of health-related instruments in CHF, and had the maximum percentage of variance in our study. Oldridge et al, in 2014 developed a 14-item questionnaire entitled HeartQoL for ischemic heart failure patients, which had two subscales of physical and emotional. They also included 10 items for the physical domain, similar to CHFQOLQ-20, and the remaining questions (4 items) were related to the emotional domain [38].
Cognitive functioning was the second underlying factor with a lower variance share than the physical domain. Cognitive disorders in HF impair self-care and lead to not reporting the signs and symptoms of disease progression in a timely manner, disability, frequent hospitalizations, decreased QoL, and increased morbidity and mortality, highlighting the significance of assessing the cognitive disorders in HF patients who are mostly elderly [39]. Despite the significance of the cognitive domain, none of the existing instruments have a cognitive domain, and only the MLHFQ [22] has an item entitled “difficulty in concentration or remembering things” which has been loaded under the emotional domain.
General health was the third underlying factor loaded with three items and mental health which was the fourth underlying factor in CHFQOLQ-20. According to the literature, 30–40% of CHF patients experience emotional distress such as depression following impaired physical function, role changes, financial insecurity, and social isolation [39]. Depression in HF patients is correlated with fear due to development of physical symptoms such as dyspnea, and functional limitations. Fear can also lead to denial of disease symptoms and result in not seeking medical attention in time [40].
Similar to HeartQoL [38], CHFQOLQ-20 did not have a social domain. Oldridge et al. explained that the social problems of ischemic heart failure patients may not be unique or strong enough to be suggested as an independent latent construct. On the other hand, the social domain items may be culture- or diagnosis-specific, and since in ischemic heart failure, different diagnoses such as angina, myocardial infarction, and ischemic heart failure are considered, social problems cannot be generalized to the aforementioned three groups of diseases [38]. Similarly, the present study was conducted on ischemic and non-ischemic HF patients with different comorbidities, different age groups, and different socioeconomic states, and showed that social problems might not be representative of common concerns for most patients. This also occurred in MLHFQ such that eventually, only two factors of physical and emotional domains were found to be meaningful clusters in MLHFQ [22].
The construct validity and internal consistency of CHFQOLQ-20 indicated that this scale is a promising instrument for assessment of HRQoL in a target population. The first assessment of this new instrument indicated emerging evidence of its validity and reliability. The item-total correlation for the total scale was high, indicating that the items measured the desired concept, and none of them had the criteria for removal. With regard to concurrent validity, the correlation between the similar subscales of the CHFQOLQ-20 and SF-36 was high and significant. Also, the significant correlation of CHFQOLQ-20 with MacNew indicated optimal convergent validity.
Minimum, maximum, and mean subscale and total scores of CHFQOLQ-20 can be used as a guide in the clinical setting. These results may serve as a unique finding in the clinical setting. Nonetheless, further evaluation of CHFQOLQ-20 is necessary. By offering the norms for each subscale of CHFQOLQ-20, the authors hope that clinicians can make correct decisions in favor of patients in well detectable areas (higher well-being versus lower well-being). For instance, clinicians can refer patients who acquire a low score in mental health domain to a psychologist for psychological counseling. Also, clinicians can optimally rehabilitate patients who have problems in physical functioning domain and acquire a low score in this domain by reenrollment in cardiopulmonary rehabilitation programs or assessment of comorbidities such as sleep apnea and improve their QoL as such. However, longitudinal studies are required to assess the responsiveness and significant clinical changes in the scores. Researchers are recommended to assess the responsiveness of CHFQOLQ-20 to determine its ability to detect significant clinical changes over time. With respect to the low frequency of the missing data, it may be stated that the new questionnaire is relevant and is not too burdensome or difficult to complete. This study did not find a clear pattern for the missing data, which indicates no emergence of systematic missing data.
Strengths And Limitations
One strength of this study was adoption of qualitative and quantitative approaches to develop the instrument based on the experiences of patients living with HF taking into account their cultural background. The participants in this study had different types of HF (ischemic and non-ischemic) and were from different socioeconomic background, which enhances comprehensive assessment of QoL of CHF patients. A rigorous methodology was another strength of this study, which included the COSMIN checklist and ICF. The CHFQOLQ-20 developed in this study showed excellent psychometric properties. This instrument had practical strengths. First of all, few missing values in this instrument indicated that it was comprehensible for patients. Also, its few items along with four unique subscales enable its application in clinical studies compared with other instruments. However, The first limitation of this instrument was that its responsiveness to detect clinical changes over time was not evaluated in this study. Another limitation was recruitment of patients by convenience sampling. Also, the information belonged to a limited geographical location. Thus, its generalizability to other geographical areas, cultures and races might be examined. Also, this study only evaluated patients presenting to HF clinics, and hospitalized patients were not enrolled. Recall bias was another limitation of this study, which might have affected the results since we asked the participants to recall the events of the past month.