The original EHFScBS-C is a nine-item questionnaire built around a two-factor structure: one factor captures medical self-care behaviours, such as ensuring the patient takes medication correctly and recognizes worsening symptoms, while the other captures lifestyle self-care, including diet, physical activity, and daily weighing. The scale has become a standard measure in European research, but a questionnaire is not simply a list of questions that can be translated word for word. Concepts such as self-care, symptom monitoring, and even the role of family members in medical decision-making carry cultural weight, and a poorly adapted instrument can produce misleading scores. The research team therefore set out to translate, culturally adapt, and statistically test the scale for use among Iranian caregivers, a process known in the field as psychometric evaluation.

The study was designed as a cross-sectional methodological investigation, the standard architecture for validation research. Between October 2023 and February 2024, the researchers recruited 260 informal caregivers of heart failure patients at Ayatollah Mousavi Hospital in Zanjan, Iran, using convenience sampling. Before any data were collected, the team carried out forward and backward translation: the scale was first rendered from English into Persian by translators, then independently translated back into English, and the two versions were compared to detect distortions in meaning. This iterative procedure, followed by expert review, is the accepted method for ensuring that a translated questionnaire asks the same questions as its original.

Face and content validity came first. Content validity asks whether the items genuinely cover the domain the scale claims to measure, and it is typically quantified with content validity indices in which experts rate the relevance of each item. In this study, the scale-level average content validity index reached 0.95, an exceptionally high value on a metric where values above 0.90 are generally considered excellent. That figure suggests the expert panel judged nearly every item to be clearly relevant and unambiguous in the Persian cultural context, with no items requiring substantive revision or deletion.

The centrepiece of the study was confirmatory factor analysis, or CFA, a statistical technique that tests whether the pattern of correlations among questionnaire items matches a predefined theoretical structure. Unlike exploratory factor analysis, which searches for structure in the data, CFA imposes the original two-factor model — medical self-care and lifestyle self-care — and asks how well it fits. The researchers evaluated fit using several complementary indices, each capturing a different aspect of model adequacy. The ratio of chi-square to degrees of freedom was 1.64, comfortably below the conventional threshold of 3. The root mean square error of approximation, or RMSEA, was 0.049, beneath the 0.05 benchmark that signals close fit. The comparative fit index and the Tucker-Lewis index came in at 0.984 and 0.978 respectively, both far above the 0.95 cutoff. Taken together, these numbers indicate that the two-factor structure of the original European scale survived translation into Persian essentially intact.

Item-level statistics reinforced that conclusion. All nine items showed statistically significant factor loadings, meaning each item reliably contributed to its intended factor, with loadings ranging from 0.407 to 0.912. Notably, the researchers did not need to remove a single item to achieve good fit, which is uncommon in cross-cultural validation work, where weak items are frequently dropped. Preserving the full nine-item structure matters practically: it means scores from the Persian version can be interpreted in the same way as scores from the original instrument, enabling meaningful comparison across studies, countries, and languages.

The team also examined convergent and discriminant validity, two complementary tests of whether the scale measures what it claims and nothing else. Convergent validity asks whether items theorized to reflect the same construct correlate strongly with one another; discriminant validity asks whether distinct constructs, such as the medical and lifestyle factors, remain statistically separable rather than collapsing into a single undifferentiated blob. The Persian scale established acceptable performance on both fronts, supporting the interpretation of two related but distinct dimensions of caregiver contribution.

Reliability — the consistency of measurement — was assessed in two ways. Internal consistency, which reflects how coherently items within a scale hang together, was quantified with both Cronbach’s alpha and McDonald’s omega, two statistics that approach the same question from slightly different assumptions. The overall scale achieved a Cronbach’s alpha of 0.834 and a McDonald’s omega of 0.894, with the subscales also showing strong values; both figures sit well within the range regarded as good for a short clinical instrument. Test-retest stability was evaluated by readministering the scale to participants after a two-week interval and computing the intraclass correlation coefficient, which came out at 0.89. An ICC of that magnitude indicates that caregivers’ scores were highly stable over time, exactly what one would expect from a measure of habitual behaviour rather than a fleeting mood state.

Why does this matter beyond the statistics? Heart failure is one of the most burdensome chronic conditions worldwide, and readmission rates remain stubbornly high in many health systems, often because patients fail to adhere to the demanding self-care regimen the condition requires. Caregivers are the hidden workforce that makes adherence possible, yet family-centred interventions can only be evaluated if caregiver contribution can be measured accurately. A validated Persian version of the EHFScBS-C gives Iranian clinicians and researchers a trustworthy tool for identifying caregivers who need support, tailoring education programmes, and evaluating whether family-centred heart failure management actually improves outcomes. The authors conclude that the nine-item scale is robust, valid, and reliable in the Iranian context, and its structural stability without item deletion makes it a practical addition to clinical practice and research. The study, published open access under a Creative Commons licence, was approved by the Institutional Review Board of Zanjan University of Medical Sciences and conducted in accordance with the Declaration of Helsinki, with written informed consent from all participants. For the millions of families quietly managing heart failure at home, this work represents a small questionnaire with a large consequence: the daily labour of love that keeps patients stable can finally be seen, measured, and supported.

Subject of Research: Psychometric validation of the Persian version of the European Heart Failure Self-Care Behaviour Scale for Caregivers

Article Title: Psychometric evaluation of the persian version of the EHFScBS-C: a confirmatory factor analysis

Article References: Yadegary, M. A., Aghajanloo, A., Shaabani, M., Masaebi, F., & Seyednazari, M. A. (2026). Psychometric evaluation of the persian version of the EHFScBS-C: a confirmatory factor analysis. BMC Nursing, 25(1), Article 913. https://doi.org/10.1186/s12912-026-05404-2

Image Credits: AI Generated

DOI: 10.1186/s12912-026-05404-2

Keywords: heart failure, caregivers, self-care, psychometrics, validation study, confirmatory factor analysis, EHFScBS-C, Iran, nursing research, reliability, questionnaire translation, family-centred care