Development and validation of a health literacy scale for family caregivers of older people with chronic illness

Background: Family caregivers (FCs) encounter a variety of health problems in older people with chronic illness, necessitating a certain level of health literacy to access, understand, appraise and apply health information and services. This study aimed to develop and validate a scale for measuring health literacy among FCs of older people with chronic illness.

Methods: Concept mapping was first employed to develop a conceptual model of health literacy of FCs. Scale domains were derived from the conceptual model, and item generation was performed using deductive and inductive methods. Quantitative methods, including merging scale dimensions and items, expert reviews, cognitive interviews, and item reduction analysis, were used to refine the scale. Confirmatory factor analysis was employed to validate the scale's structure. Concurrent validity, internal consistency, and test-retest reliability were also examined.

Results: A 20-dimension conceptual model was developed, and 60 items were generated for the scale. Expert review (content validity index > 0.85) and cognitive interview with FCs confirmed the relevance and clarity of the majority of the generated scale items. Confirmatory factor analysis with 451 FCs of older people with chronic illness supported a 5-factor structure (symptom management, daily personal care and household tasks, care coordination, communication and relationship with the care recipient, and self-care of caregivers) with 42 finalized scale items, including four levels of health literacy skills (accessing, understanding, appraising and applying health information). Concurrent validity with the European Health Literacy Questionnaire (HLS-EU-Q47) was satisfactory (r = 0.67, p < 0.01). The Cronbach's α coefficient of the scale was 0.96, with subscales ranging from 0.84 to 0.91. The two-week test-retest reliability was 0.77 (p < 0.01).

Conclusion: This study developed a conceptual model explaining the concept and factors of health literacy among FCs of older people with chronic illness that could provide the groundwork for future studies in developing relevant evidence-based interventions. A new Health Literacy Scale-Family Caregiver (HLS-FC) with satisfactory psychometric properties was developed in this study, which can be utilized to identify caregivers with insufficient health literacy and facilitate timely interventions by healthcare professionals.