When language shapes measurement and care models: validating caregiver strain among relatives of out-of-hospital cardiac arrest survivors

This invited commentary refers to ‘Translation, cross-cultural adaptation, and psychometric properties of the Danish version of the Modified Caregiver Strain Index (M-CSI) among relatives of out-of-hospital cardiac arrest survivors’ by S. B. Bruvik et al. https://doi.org/10.1093/eurjcn/zvaf226. Caregiver strain among survivors of out-of-hospital cardiac arrest (OHCA) has emerged as a critical yet underexplored dimension of post-cardiac arrest care, reflecting the complex interplay between patients’ neurological, cognitive, and psychosocial sequelae and the sustained demands placed on informal caregivers. In this context, the use of caregiver-reported outcome measures is essential to capture outcomes that extend beyond traditional clinical endpoints. However, the validation specifically of caregiver-reported outcome measures in OHCA populations remains limited, and the existing instruments risk to be applied without full validation in this population, potentially limiting their interpretability. Translation and adaptation usually go beyond linguistic equivalence. Terms may carry culturally specific assumptions regarding family roles, gender expectations, and social welfare systems. As articulated by Beaton et al.1 and reinforced by COSMIN guidelines,2,3 cross-cultural adaptation must ensure four crucial and different levels of equivalence: the semantic (word meaning), the idiomatic (colloquial expressions), the experiential (relevance to lived context), and the concept (construct comparability across cultures). According to methodological literature, conceptual equivalence should take precedence over literal translation.3 The Danish adaptation described by Bruvik et al.4 demonstrates sensitivity to the above-mentioned nuances, particularly through cognitive interviewing. Importantly, the study stands out for its rigorous translation and cross-cultural adaptation process, which actively incorporated participants’ perspectives. The use of cognitive interviewing techniques, such as the think-aloud approach, strengthens confidence that the instrument is both understandable and contextually relevant. This aspect is not trivial. Cognitive interviewing (think-aloud and verbal probing techniques) used by Bruvik et al.4 as a validity safeguard plays a pivotal role in detecting misinterpretation, ambiguity, and culturally embedded assumptions. In cardiovascular populations, where emotional trauma and existential concerns frequently coexist with physical caregiving demands, subtle shifts in wording may alter item interpretation. The Danish study’s minor refinements following cognitive testing illustrates that small linguistic adjustments may prevent large psychometric distortions, whereas emotional salience may amplify interpretive variability. The study showed no statistically significant differences in the correlation between strain scores and variables such as gender, relationship to the patient, and cohabitation. In contrast, a statistically significant correlation emerged between younger age and higher strain scores. Moreover, in relation to the Hospital Anxiety and Depression Scale (HADS) and the World Health Organization’s Five Well-being Index (WHO-5), used to assess the instrument’s convergent validity, a stronger alignment with emotional burden (HADS) was confirmed. This suggests that the greater strain experienced by relatives may derive more from emotional reactions and concerns than from practical inconveniences. Under the psychometric point of view, the authors appropriately employed exploratory factor analysis (EFA) to examine the latent structure of the M-CSI, a reasonable choice given the ongoing uncertainty surrounding its dimensionality. The variability in factorial structures reported across studies may, in part, reflect the limited involvement of caregivers during the original development of the M-CSI, where a formal content validity phase was lacking. Without direct input from the target population, items may be interpreted differently across contexts, ultimately influencing the observed psychometric structure. From this perspective, the careful cultural adaptation performed in the present study may have reduced misinterpretations, thereby contributing to the emergence of a coherent one-factor solution. From a methodological point of view, the use of polychoric correlations and parallel analysis represents a clear strength and aligns with current recommendations for conducting EFA with ordinal data. However, the interpretation of the one-factor structure should remain cautious. Exploratory factor analysis, by definition, is exploratory, and the absence of a confirmatory factor analysis (CFA) limits the robustness of the conclusions. Without formal model testing, it remains unclear whether the unidimensional structure reflects the underlying construct of caregiver strain or is partly driven by sample-specific characteristics. In this regard, testing alternative models (one-, two-, and three-factor solutions) within a confirmatory framework would have provided a more comprehensive understanding of the instrument’s dimensionality and allowed a direct comparison of competing theoretical structures. Overall, while the findings support a unidimensional interpretation of caregiver strain in this population, they should be viewed as an important step rather than a definitive conclusion. Further validation using confirmatory approaches and more advanced psychometric models (e.g. item response theory) would be essential to fully establish the structural validity of the M-CSI. For clinicians, these results reinforce the relevance of having a tool for detecting strain among caregivers, including relatives of individuals discharged after a cardiac arrest. The translation and cultural adaptation carried out by the Danish researchers also revealed the strong correlation between strain and emotional reactions and concerns, confirming previous research on post-cardiac arrest discharge. Furthermore, for the broader cardiovascular community, the study establishes an important benchmark in identifying areas where further research is needed to design and implement targeted support (considering that the emotional burden experienced by relatives of individuals discharged after cardiac arrest may significantly affect their psychophysical health), suggesting the need to explore caregiver strain to achieve a comprehensive understanding and provide adequate support. The article also raises an important question regarding the hypothesis for targeting support. In this regard, several steps still need to be taken: once the level of caregiver strain has been identified, it becomes essential to determine which interventions are evidence-based and appropriate to address this burden, which healthcare professionals are best suited to deliver such interventions (e.g. psychologists, rehabilitation specialists, or multicomponent interventions combining education, psychological support, caregiver inclusion in rehabilitation, and peer support), and in which care settings these services should be implemented. Emerging evidence points to digital and psychological interventions embedded in survivorship programmes.5 Although not exclusively caregiver-focused, such interventions reflect a scalable model for integrated psychosocial support. Additionally, while gaps persist in its methodological assessment, recent contributions highlight the possible relevance of new elements like the clinical ethics consultation (CEC) services, in recognizing and promoting the resolution of the existential burdens and moral distress experienced by healthcare professionals, patients, and families, which frequently underlie conflicts in clinical practice.6 The benefits reported in de-escalating uncertainties and tensions are promising, suggesting that CEC might be a valuable component of the intervention to be implemented as a structured support service for caregivers, especially in addressing ethically complex situations. Finally, considerations about the organization of care delivery regarding the interventions, including reimbursement models and resource allocation, are necessary to ensure that psychosocial support is both accessible and sustainable. In conclusion, as healthcare becomes increasingly globalized, carefully elaborated cross-cultural methodology is indispensable. The Danish M-CSI validation exemplifies careful adaptation grounded in contemporary standards and provides a solid foundation for future comparative work. In summary, the study by Bruvik et al.4 represents a relevant contribution to the understanding of strain experienced by relatives of cardiac arrest survivors, confirming the clinical value of the M-CSI and highlighting the importance of the emotional components of caregiver strain. However, the methodological limitations identified by the authors suggest the need to further explore this experience through more comprehensive, multidimensional analyses that integrate the caregiving role, the care context, the evolution of perceived burden over time, and the cultural and social expectations of caregiving roles. By conducting a more detailed assessment of caregiver strain, it may be possible to identify relatives’ needs better and design targeted support interventions that improve caregivers’ well-being. Angela Durante (Conceptualization, Writing—original draft, Writing—review & editing [lead]), Marco Di Nitto (Conceptualization [equal], Writing—original draft [lead], Writing—review & editing [supporting]), Anna Gadignani (Writing—original draft [equal], Writing—review & editing [supporting]), and Yuliia Lysanets (Conceptualization, Writing—original draft [equal], Writing—review & editing [supporting]) None declared. This commentary does not contain any new data.