Oral anticoagulation (OAC) with warfarin is still widely used in various clinical situations, such as in metallic prostheses. However, managing warfarin presents well-known challenges, including its narrow therapeutic range, long half-life, frequent drug and food interactions, and genetic variations. Additionally, poor adherence to treatment and lack of awareness about atrial fibrillation (AF) and anticoagulation itself significantly contribute to unfavorable clinical outcomes. Even with the use of direct oral anticoagulants (DOACs), there are still peculiarities among the different therapeutic options, which are often poorly communicated to the patient. This compromises the necessary understanding for effective disease management and highlights gaps in patient knowledge.¹

Social determinants of health play a fundamental role in individuals’ health conditions. Factors such as race/ethnicity, socioeconomic status, education level, environment, and climate, among others, have a direct impact on the incidence and management of chronic diseases, such as AF. Several studies indicate that people in situations of socioeconomic vulnerability — including low income, low education levels, and unemployment — show a higher prevalence of AF.^2-4

In this context, the article by Souza et al.,⁵ published in this issue and entitled "Association Between Functional Health Literacy and the Quality of Oral Anticogulation," analyzed the relationship between patients’ knowledge about the use of oral anticoagulants and the effectiveness in controlling the International Normalized Ratio (INR) over 18 months. In the study, the instrument "Short Assessment of Health Literacy for Portuguese-speaking Adults (SAHLPA-18)," validated in Portuguese by Paiva et al.⁶ was used.

The authors observed that, although the level of functional health literacy was not directly associated with the time in therapeutic range (TTR), low literacy levels negatively influenced the persistence of adequate anticoagulation over time.

The term "health literacy" was introduced by Don Nutbeam in 1998 in the Health Promotion Glossary. He defined it as a set of cognitive and social skills that determine individuals’ motivation and ability to access, understand, and use information to promote and maintain good health.⁷ Although the term alfabetização (alphabetization) is also used in Portuguese, it is important to differentiate them: while alphabetization is related to learning letters and written symbols, literacy refers to the ability to use language in social practices, involving comprehension, interpretation, and application of knowledge.

Peres et al.⁸ expanded this concept by defining health literacy as a set of skills that influence how individuals use health information—from reading and writing to understanding complex biological processes.

Health literacy is essential for developing effective health education strategies and reducing complications associated with the use of oral anticoagulants. Health literacy provides patients with tools to better understand their clinical condition and treatment, contributing to greater therapeutic adherence and more appropriate anticoagulation management.⁸ Studies have shown that inadequate health literacy levels are associated with worse clinical outcomes, including increased morbidity and mortality.^9,10 The study by Souza et al.⁵ demonstrates that it remains a significant challenge in patient care.