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

ABSTRACT

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 ‘fixed-dose regimen’ drugs are characterized by not requiring routine monitoring or dosage adjustment. Stroke prevention with OAC is indicated in AF patients with CHA₂DS₂-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.

KEYWORDS:

• Atrial fibrillation
• oral anticoagulants
• adherence
• stroke
• bleeding

Article highlights

• NOACs are at least as effective as VKAs for prevention of stroke and mortality in atrial fibrillation (AF), and safer in terms of major bleeding complications but non-adherence and discontinuation of oral anticoagulation (OAC) is closely related to worse clinical outcomes.

• The anticoagulant effect of NOACs is non-monitored and the doses are fixed. Although a fixed-dose regimen might improve patients’ adherence, the fear of bleeding, especially in the elderly, those with low body weight and renal dysfunction can lead to an underprescription or underdosing/overdosing on NOACs

• There are several barriers to optimal adherence and persistence so new strategies should be implemented. Better education about AF and stroke risk, as well as specific information about anticoagulant treatment and the potential consequences of non-adherence would help to better understand of the importance of OAC by patients.

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Declaration of interest

GYH Lip is a Consultant for Bayer/Janssen, BMS/Pfizer, Biotronik, Medtronic, Boehringer Ingelheim, Microlife and Daiichi-Sankyo. Speaker for Bayer, BMS/Pfizer, Medtronic, Boehringer Ingelheim, Microlife, Roche and Daiichi-Sankyo. JM Rivera-Caravaca is supported by Instituto Murciano de Investigación Biosanitaria (IMIB16/AP/01/06) and has received a grant from Sociedad Española de Trombosis y Hemostasia (SETH; grant for short international training stays 2016). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

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Funding

This paper has not been funded.