Adherence to oral thromboprophylaxis in atrial fibrillation: an overview for clinicians

In most patients with atrial fibrillation (AF), effective stroke prevention necessitates long-term (often lifelong) oral anticoagulant therapy (OAC). However, the effectiveness of OAC therapy in a clinical setting (i.e. outside the controlled environment of randomized clinical trials) is strongly influenced by patients' adherence and persistence with prescribed therapy. However, suboptimal adherence to OAC remains a substantial problem in routine practice-available evidence suggests that patients do not take their OAC one out of every four days, and approximately one in three to four patients is poorly adherent to OAC. In addition, around 15% of high-risk OAC-eligible patients with AF refuse to take OAC for a variety of patient-specific reasons. Poor adherence to OAC therapy is associated with adverse clinical outcomes [such as stroke or systemic embolism, hospitalization, mortality, bleeding (particularly with vitamin K antagonist therapy)] and increased economic costs. In this overview, we summarize important aspects of the adherence to medication concept, including the definition and measurement of adherence, the determinants and prevalence of OAC non-adherence, the clinical importance of achieving and maintaining good adherence, strategies to improve adherence to OAC, and alternative treatment options for effective thromboprophylaxis in patients with AF who are non-adherent to OAC therapy.