Health literacy (HL) refers to the individual (skills, abilities, and knowledge) and social factors that influence the acquisition, processing, and understanding of information related to health and health-related systems in order to make appropriate decisions for the well-being of the individual (1). Additionally, HL includes the ability to read and understand health instructions, or follow treatment plans. HL is determinant in the prevention and management of chronic diseases such as diabetes, chronic kidney disease, and chronic obstructive pulmonary disease (COPD), and it is closely linked social determinants fuelling social and health inequalities (2, 3). Patients with low HL have difficulties with therapeutic concordance and effective disease management, resulting in worse health outcomes, higher hospitalization rates, and lower quality of life (4, 5).

Although HL is a determinant of health protection and disease prevention, it is in itself also influenced by a wide range of personal, social, and structural variables (6–8). Among these factors, for example, schooling, socioeconomic status, and gender-albeit from an intersectional lens and as a reflection of inequalities in access to education (7, 9, 10)-as well as urbanicity (11) have been described. Measuring HL is essential to identify inequalities in access, understanding and use of health information, which allows for the design of more effective and equitable interventions. There are multiple tools developed in recent decades, such as the rapid estimate of adult literacy in medicine (REALM), the test of functional health literacy in adults (TOFHLA) and the newest vital sign (NVS), which have been widely used, although they have limitations by focusing primarily on functional literacy and not addressing broader dimensions such as critical or communicative literacy (12). More recent instruments, such as the health literacy questionnaire (HLQ) and the European health literacy survey questionnaire (HLS-EU-Q47), offer a more comprehensive assessment by considering multiple dimensions of health literacy (13). However, the lack of consensus on the dimensions assessed and the variability in the psychometric properties of these tools indicate the need to develop more robust instruments adapted to diverse population contexts. Accurate measurement of HL is essential to improve health outcomes and reduce existing inequalities (14).

Heart failure (HF) is a chronic and progressive health problem affecting more than 64 million people worldwide (49). Optimal management is multimodal, including pharmacological therapies, assistance and continuous healthcare, and high patient involvement in self-management (15). HL is therefore equally crucial in the management of HF; people with HF and low HL have worse health outcomes, including higher rate of re-hospitalizations and mortality (16, 17), as well as higher frailty burden (18), worse self-care skills (19) and reduced quality of life (20). According to a study by Smith et al. (21), greater understanding of medical information reduces these cardiovascular risks. According to Cabellos-García et al. (22), patients with low literacy have 30% higher cardiovascular risk and increased undesirable health outcomes. For example, inadequate management of arterial hypertension, poor cholesterol control or problems following a certain diet, all of which are fundamental risk factors in the control of cardiovascular problems (49).

Consequently, appropriate lifestyles and capacity for the management, control and evaluation of HF are key, and are modulated by the level of HL. This can be done by patients themselves, but also by their caregivers, as it is very common for patients to need partial or total support from a caregiver at advanced stages of the disease. In these cases, the caregiver plays a substitute role that includes decisions about the patient’s diet or activity, pharmacological treatment and management of appointments with professionals, or decisions such as whether or not to go to the emergency room. Regardless of who performs it, it is what we know as self-care (23), a key concept that can be known since it can be measured, for example with the European heart failure self-care behavior scale (EHFSCBS), a scale that measures self-care capacity in a brief form in both patients and caregivers (24).

HL competencies associated with communication and socialization are critical. In general, there is a positive association between self-care and social support, key factors for effective HF management (18), and people with higher HL have greater needs for communication about their disease and self-care (25). Finally, the HL level of caregivers also influences the self-care of people with HF (26). This information can inform us about patients or caregivers who may have compromised their ability and skills to live with their disease, their self-care, and their capacity for correct decision making. Knowing this information would allow us to implement actions aimed at improving these skills and controlling the risk of undesirable events.

To improve HL in people living with HF, various interventions have been developed. These include assessing HL using validated questionnaires and its impact on therapeutic adherence (27), personalized education (28), care models based on nurses supported by digital platforms, and programs aimed at improving the HL of caregivers (26). It is therefore necessary to conduct research that analyzes the level of health literacy and its relationship with quality of life in this population, in order to design more effective and personalized educational interventions and care strategies.

Thus, we set out to determine the level of HL and self-care in a sample of people with HF, and to describe the relationship between this level of self-care and clinical and sociodemographic variables routinely collected during social and health care in a referral center. Secondarily, we intend to explore the predictive validity of the level of HL (measured with HLS-EU-Q16) on the self-care capacity of people with HF and their caregivers.

Of 321 patients eligible to participate (266 males and 55 females), 35 patients were excluded due to age, 33 patients died, and 57 patients could not be located or did not wish to participate. Therefore, the final sample size was 195 patients (162 males and 33 females). The median age of the participants was 69.26 ± 9, mostly of middle social class (87.7%), and with basic education (64.6%) (Table 1).

Our study analyzed health literacy (HL) and self-care in patients with heart failure (HF) in a region of Spain using validated questionnaires (HLS-EU-Q16 and EHFScBS, respectively). Sociodemographic factors such as sex, educational level, or perceived social class, influence different dimensions of HL, whereas age and educational level influence self-care.

As with other health problems, HL is essential for maintaining the health of people with HF (31). HL enables effective communication with healthcare professionals, appropriate treatment follow-up, and informed decision-making about self-care, while also fostering critical and social skills that empower patients in their daily lives and healthcare environments (32). Conversely, low HL is associated with poorer medication adherence, greater use of emergency services, worse disease control, and higher risk of hospitalization (27, 33).

In line with the literature, educational level in our participants was positively associated with higher scores across multiple HL dimensions, reinforcing the importance of formal education in promoting health competencies (34). Another factor closely linked to education and likewise associated with better HL was perceived social class, which reflects a confluence of structural factors (e.g., economic resources and opportunities for personal development) (35).

In our study, participants at upper-middle social class had lower self-care. This counterintuitive finding could be explained by behaviors related to the delegation of care to other people, more stressful lifestyles, lower risk perception, or greater confidence in healthcare interventions versus self-care. Poor self-care behaviors have been previously described in populations with higher income or at higher socioeconomic position in highly prevalent chronic conditions such as diabetes (36, 37). Specifically, Walker et al. (37) found that higher household income (>$75,000) was associated with poorer self-care regarding exercise, in terms of fewer days per week of physical activity and lower performance. By contrast, in Burch et al.’s study (36), individuals at higher socioeconomic position performed more exercise and consumed more vegetables; however, they also exhibited worse self-care behaviors than individuals in lower social position regarding self-monitoring of blood glucose, foot inspection and care (prevention of diabetic foot), and treatment adherence. Thus, we argue against individualistic perspectives of HL and support the importance of the socioeconomic context of individuals (18, 32).

Regarding self-care, our older and less educated participants had higher scores on the EHFScBS scale, or lower level of self-care. These findings suggest a weak, but significant, relationship between older age and specific components/dimensions of HL in certain specific aspects. These results coincide with previous studies focused on self-care in heart failure (38). In Cajita et al. (39), patients with better HL were more competent in monitoring and managing their HF. In our study, however, the HL-HF association was positive with self-care maintenance. In previous studies, patients with higher HL might follow better maintenance activities, such as medication adherence and symptom monitoring, but might not be as proactive in managing acute symptoms (40). These findings could reflect the complexity and multi-factoriality of the relationship between HL and self-care, including the relative contribution of factors already mentioned such as age, educational level, social support, or others such as comorbidities (41), perceived self-efficacy, or intrinsic motivation (40, 42).

Beyond individual abilities, the social component—through mutual support and coping styles—indirectly shapes symptom burden and remains an undervalued, underexploited lever in therapeutic interventions (43). Consistent with this, HL in people with CHF may influence symptom burden indirectly via social support and coping, with a need to design interventions tailored to each person’s capabilities and context (27, 33, 43). Moreover, the association between HL and self-care obtained in our study highlights the importance of integrating interventions in both areas to foster optimal self-care behaviors.

With respect to sex, our results show that, compared with men, women reported significantly higher scores on several items of the HLS scale. This finding could be related to sociocultural, gender role and behavioral factors in accessing and using health information (44), and suggesting greater female involvement in health care and information seeking related to health (13, 45). This pattern supports the need to incorporate a gender perspective when designing educational interventions to maximize effectiveness.

Accordingly, the most successful educational interventions in people with HF have been those personalized (46), such as structured and individualized educational programs that have significantly improved knowledge of the disease and therapeutic adherence. Clear guidance would still be lacking to address this synergy of HF promotion activities with self-care, with interventions that are not only effective but also scalable scientific (31), as well as assessing the sustainability of long-term effects and their impact on clinical outcomes such as hospitalizations and mortality (31, 42, 47).

Regarding clinical variables, no significant differences in HL or self-care were found between patients with or without hypertension, dyslipidemia or smoking. However, specific differences in self-care items were identified in people with diabetes, obesity and dyslipidemia, suggesting a possible influence of certain comorbidities. The frequency of hospitalizations and consultations was not consistently associated with HL, although some items showed point correlations, possibly linked to the perception of symptoms or need for care (42). Finally, although the NYHA classification did not show global differences in the scales, certain self-care items did correlate with clinical stage, which could reflect behavioral adaptation rather than differences in HL.

A secondary objective in our study was to explore the predictive capacity of HL screening on self-care capacity in HF. In this respect, the results appear conclusive: low HL scores may result in poorer HF management ability. Jiménez-Méndez et al. (48) argue that good predictive validity—the ability of a tool to accurately predict future outcomes—would help identify patients at high risk of decompensated HF, which, as shown, often results from self-care deficits. Identifying these at-risk patients will facilitate the implementation of personalized preventive strategies.

HL in people with HF is associated with factors such as sex, educational level, and socioeconomic position. However, these findings underline that, although clinical research provides valuable data, sustained improvement of HL and self-care in HF requires structural social interventions, beyond the clinical setting. There is a need to move toward approaches that integrate public policies, tailored educational strategies, and cross-sectoral actions that address the structural inequalities that underlie differences in HL. Increasing evidence is useful, but the real impact will come from social interventions that promote critical, equitable, and contextualized literacy.