Treatment Changes among Users of Non‐Vitamin K Antagonist Oral Anticoagulants in Atrial Fibrillation

Abstract

Patients with atrial fibrillation discontinuing anticoagulant therapy are left unprotected against ischaemic stroke. Further, switching between oral anticoagulants may be associated with a transiently increased risk of bleeding or thromboembolism. However, there is a paucity of real-life data on pattern of switching and discontinuation of oral anticoagulants. To address this, we conducted a nationwide drug utilization study including all registered Danish atrial fibrillation patients initiating a non-VKA oral anticoagulant (NOAC) between August 2011 and February 2016. We assessed changes in anticoagulant treatment, including switching between oral anticoagulants and discontinuation of NOACs, and explored patient characteristics predicting these changes.We identified 50,632 patients with atrial fibrillation initiating NOAC therapy within the study period. The majority initiated dabigatran (49.9%) and one-third had previously used VKA. Within 1 year, 10.1% switched to VKA, 4.8% switched to another NOAC and 14.4% discontinued treatment. The frequencies of switching to VKA and discontinuation were highest among NOAC users of young age (<55 years) and with low CHA 2 DS 2 -VASc score (=0). However, the majority of patients (87.3%) stopping NOAC treatment had a CHA 2 DS 2 -VASc score ≥1.We conclude that switching from VKA to NOAC, and to a lesser extent from NOAC to VKA, is common, as is early treatment discontinuation. The majority of treatment changes are observed in patients at increased risk of stroke. More research is warranted on the risks of bleeding and thromboembolism associated with switching and discontinuation of NOACs as well as the underlying reasons why these treatment changes occur.

Incidence of direct oral anticoagulant use in patients with nonvalvular atrial fibrillation and characteristics of users in 6 European countries (2008–2015): A cross‐national drug utilization study

“…Several national/regional studies have reported increases in the number of DOAC users, despite the NVAF population used differing from ours . The incidence increased in both the males and females across the study period in most databases.…”

“…To our knowledge this is the first cross‐national drug utilization study providing the incidence of DOAC use in NVAF patients at a national/regional level, across several European countries. Only a few, single country European studies with similar inclusion criteria have been published, which only provide number of DOAC users rather than incidence figures …”

“…Clinical trials have shown that both vitamin K antagonists and DOACs reduce stroke and mortality in AF patients . Utilization of DOACs for stroke prevention in NVAF and their effectiveness and safety in clinical practice have been assessed in several European countries . However, little is known about their use beyond clinical trial conditions, especially in patients with hepatic or renal impairment.…”

Use of direct oral anticoagulants in the first year after market entry of edoxaban: A Danish nationwide drug utilization study

“…Importantly, these DOAC users without a registered indication were older, more frequently had a history of ischaemic stroke, and more often received low‐dose DOAC compared with DOAC users with a registered indication. Therefore, the exclusion of DOAC users without a registered indication may constitute an important selection bias in observational studies based on the Danish health care registries, as pointed out previously …”

Switching, Adverse Effects and Use of Over‐the‐Counter Analgesics among Users of Oral Anticoagulants: A Pharmacy‐based Survey

“…Furthermore, the sex distribution in our sample is similar to that of sex‐stratified data on all drug sales of OACs in Denmark in 2015 (made available from Danish online drug statistics ). In our study, no patients stated to fill NOAC due to ‘upcoming/recent knee‐ or hip replacement’, although register‐based studies have found this to be the indication of around 10% of all newly initiated NOAC treatments . This may be explained by these patients only being prescribed a NOAC once and therefore being less likely to be captured in this setting.…”