Non-vitamin K antagonist oral anticoagulants: impact of non-adherence and discontinuation

Introduction: Non-Vitamin K Antagonist Oral Anticoagulants (NOACs) are at least as effective as vitamin K antagonists (VKAs) reducing thromboembolism and mortality in atrial fibrillation (AF). These 'fixeddose regimen' drugs are characterized by not requiring routine monitoring or dosage adjustment. Stroke prevention with OAC is indicated in AF patients with CHA(2)DS(2)-VASc >= 2 (>= 3 in females) and NOACs are recommended in preference to VKAs. However, underuse, premature discontinuation of treatment and non-adherence to guidelines is common, and independently associated with higher stroke risk and all-cause mortality. Areas covered: In this review, we provide an overview of the impact of under or overdosing NOACs in AF patients. We debate the current adherence to AF-guidelines, the reasons involved in non-adherence and discontinuation, as well as the limitations found by patients and physicians about the use of NOACs. Expert opinion: The more convenient non-monitored and fixed-dose regimen of NOACs might improve patients' adherence but may hinder the identification of patients with poor adherence or discontinuation. Since there are several reasons for OAC underuse, future strategies to improve adherence should be implemented, that include more and better education about AF and stroke risk, as well as and specific information about the potential consequences of non-adherence to OAC.