Knowledge and medication adherence of oral anticoagulant-taking patients in Vietnam

Background: Oral anticoagulants for venous thromboembolism are not thoroughly managed in ambulatory settings in low-/middle-income countries, primarily because of patients' neglect of medication knowledge and adherence. Objectives: This study was conducted to investigate patient knowledge, adherence, and the associated factors at a Vietnamese tertiary hospital, serving as a reference for educational programs in other local and regional health care facilities. Methods: A randomly recruited cross-sectional study was conducted on patients using vitamin K antagonists (VKA) or direct oral anticoagulants (DOAC). The primary and secondary outcomes were the knowledge score (in percent) and adherence to oral anticoagulants. Student's t-tests or chi-squared tests were used to compare the crude differences in mean or proportion between patients taking VKA and DOAC. Regression models were conducted to adjust the potential confounders and determine factors associated with patient knowledge and adherence. Results: A total of 199 patients were included. After adjusting for potential confounders, patients receiving a DOAC had similar knowledge scores and levels of adherence compared with those taking VKA, with both groups being suboptimal. Previous counseling was associated with higher knowledge. Better medication knowledge, female sex, and no history of venous thromboembolism were associated with better adherence. Conclusion: Good knowledge and adherence of oral anticoagulant-taking patients remain limited in Southeast Asian clinical practice. Further studies in similar settings should examine the associations between these factors and the effectiveness of the regimens. More effective measures targeting patient knowledge and adherence should be implemented to optimize anticoagulation therapy, improve the patients' outcomes, and mitigate the associated adverse effects.