Patients with atrial fibrillation (AFib) may be able to reduce their risk of developing dementia by taking direct-acting oral anticoagulants (DOACs) instead of warfarin, according to a new study published in the Journal of the American Heart Association.[1]
The study’s authors tracked data from nearly 19,000 primary care patients in Australia who were diagnosed with AFib from 2010 to 2017. All patients had no prior history of stroke, and patients were excluded if they developed dementia within a year of diagnosis. The mean patient age was approximately 72 years old, 52.9% were men and the mean follow-up duration was 3.7 years.
A majority (60.7%) of these patients received OAC therapy for at least 80% of the follow-up period. While 48.7% of that group received a DOAC, 23.4% received warfarin. The remaining patients “received either a DOAC or warfarin at different times.”
AFib patients prescribed an OAC were more likely to present with hypertension or diabetes than patients who were not prescribed an OAC. They also had a higher mean CHA2DS2-VASc score.
Overall, the authors found, 425 patients were diagnosed with dementia. Being diagnosed with dementia was significantly less likely among patients who were prescribed some form of OAC therapy.
Looking a little closer at the data, patients receiving DOACs faced a 50% lower risk of developing dementia than patients receiving warfarin. There was not a significant difference between warfarin patients and patients who did not receive any form of OAC therapy.
“A possible explanation for the higher risk of dementia in patients receiving warfarin may be difficulty in managing the time in therapeutic range for the international normalized ratio,” wrote lead author Woldesellassie M. Bezabhe, BPharm, MSc, a specialist with the University of Tasmania in Australia, and colleagues. “Time outside the therapeutic range in these patients can lead to microemboli and microbleeds, which could cause chronic cerebral injury and finally lead to dementia.”
Bezabhe et al. did emphasize that the “dementia protective effect” of DOAC therapy compared to warfarin should be “interpreted with caution” due to the study’s somewhat brief mean follow-up period. One similar study with longer follow-up times did not show such a relationship, they added, but that analysis did have “other limitations.”
Also, the authors noted, they worked under the assumption that medication was taken by patients as recommended.
“We did not have data on actual adherence with therapy,” they wrote.
Related Content on Oral Anticoagulation Therapies:
AFib patients able to safely transition from warfarin to a DOAC
Half-dose DOAC improves outcomes after LAAO
Many nonvalvular AFib patients skip DOAC therapy altogether
LAAC or DOACs? How treatment strategies for AFib impact long-term outcomes
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Michael has more than 16 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.