Health literacy: Is it important for cardiovascular disease prevention?

The concept of health literacy has received increasing interest from health scientists and policy-makers during the last 40 years. Originally developed in the context of public health, it is now acknowledged as a key determinant of health at both the society and individual levels, in healthy people and in those with diverse communicable and non-communicable diseases.1 According to a recent comprehensive definition by the European Health Literacy Survey, health literacy refers to the ‘knowledge, motivation and competencies to assess, understand, appraise and apply health-related information within healthcare, disease prevention and health promotion settings’.1,2 Multiple population-based studies have shown a consistent relationship between low health literacy and poorer health conditions.1 In general, low health literacy is associated with less participation in health promotion and disease detection activities, risky health behaviours and diminished management of chronic diseases, resulting in increased morbidity and premature death.1 With respect to cardiovascular disease (CVD), a large population-based study in patients with CVD, published recently in this journal, has shown that low health literacy is significantly associated with less physical activity, an unhealthy diet, smoking and both underweight or overweight.3 In this issue, a multinational study group from the UK, Australia, Brazil, China, Hong Kong, Malaysia and Taiwan presents data on the association of health literacy with sociodemographic characteristics in patients with familial hypercholesterolaemia.4 Based on data from >700 patients, they found marked national differences with respect to health literacy, with more inadequate levels of health literacy in China (37%), Malaysia (25%) and Brazil (22%) compared with the UK (7%), Australia (19%), Hong Kong (16%) and Taiwan (18%).4 Low health literacy was strongly associated with higher age and lower levels of education or income, and the latter was an independent predictor for low health literacy even when adjusted for age.4 These researchers conclude that low health literacy in familial hypercholesterolaemia is associated with low income and that interventions in this disease should take the higher educational needs of these patients into account.4 These findings contribute to the growing evidence that health literacy is not independent of other psychosocial characteristics. A systematic review on the association of health literacy with sociodemographic variables, health behaviours and clinical outcomes in patients with coronary artery disease found significant associations of low health literacy with higher age, male sex, non-white ethnic groups, lower educational level, lower income and lower levels of social support.5 Low health literacy was consistently associated with more hospital readmissions, a lower health-related quality of life and higher anxiety.5 There was no significant association between health literacy and health behaviours, but the authors highlight the paucity of studies and methodological limitations, which could have concealed an association.5 Although health literacy as such is not measured in most studies, there is extensive evidence that psychosocial risk factors, such as low socioeconomic status, social isolation, chronic stress, depression and mental comorbidities are related to unhealthy lifestyles, a reluctance to change behaviour and poorer clinical outcomes in patients at risk of, and with, CVD.6 Together with evidence from various other chronic conditions,1 it is likely that low socioeconomic status and other psychosocial risk factors are also associated with low health literacy in patients at risk of and with manifest CVD. These findings on health literacy are relevant to the prevention of CVD. But what interventions are suitable for enhancing health literacy? Data on the impact of CVD preventive efforts on health literacy and its relation to health outcomes are scarce. One randomized control trial evaluated the effects of an educational intervention on health literacy and health behaviours in patients with coronary artery disease.7 Patients with low health literacy had larger improvements in their knowledge of coronary artery disease compared with patients with high health literacy and the effects on health behaviours were comparably positive.7 A secondary analysis of another randomized control trial8 evaluated the mediating effects of health literacy in a hospital-based educational intervention on medication adherence in patients after acute coronary syndrome. Although there was no global association of non-adherence and health literacy, there was evidence that patients with mild cognitive impairment might benefit from the intervention.8 By contrast, we have gained extensive knowledge about which interventions are suitable for CVD prevention and it is most likely that these interventions could also enhance health literacy. The 2016 European Guidelines on Cardiovascular Disease Prevention in Clinical Practice6 have recommended a broad range of interventions, from population-based approaches such as banning tobacco use, promoting healthy food choices and physical activities, to group-based, multimodal interventions in patients to facilitate lifestyle changes and coping with illness, and specific recommendations for individual caregiver–patient interactions to foster adherence to medication.6 There is robust evidence that these interventions are effective with respect to morbidity, mortality and quality of life6 and many countries have implemented such interventions, at least in rehabilitation settings. However, as low health literacy tends to cluster with various psychosocial risk factors, we have to recognize that studies about the extent to which guideline recommendations on psychosocial factors are implemented in clinical practice are disappointing. For example, Pogosova et al.9 reported data from the EUROASPIRE IV survey. Depressive symptoms could be assessed in 31% of women and 20% of men and anxious symptoms were found in 39% of women and 22% of men. Depression was especially associated with current smoking, central obesity and self-reported diabetes. Despite the high prevalence of depressive and anxious symptoms, there were low treatment rates with antidepressant or anxiolytic medication at discharge from hospital (2.4% of all patients) and 1.4 years thereafter (2.7–5.0%).9 We need to determine the barriers to implementation of guidelines with respect to psychosocial issues, but, to the best of my knowledge, there has so far been no study on this specific topic. Studies are also lacking on how to enhance health literacy in specific subgroups (e.g. based on ethnicity, age, sex and socioeconomic status) of patients at risk of and with manifest CVD. More studies in health services research on the implementation of psychosocial screening and treatment and methodologically sound clinical intervention trials on how to effectively enhance health literacy are therefore needed. The author declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. The author received no financial support for the research, authorship, and/or publication of this article.