Anticoagulants, Dementia and Atrial Fibrillation

The prevalence of dementia and atrial fibrillation (A-Fib) are both on the rise with the aging population and increasing burden of vascular risk factors.

The association between A-Fib and dementia is well documented. To describe that relationship, researchers use the term “strongly associated” rather than explicitly state that A-Fib causes or leads to dementia. That’s as far as they can go, because there might be other factors at play.

A-Fib Linked with Dementia

As patients, we use more direct language. All things being equal, we say A-Fib leads to and/or causes dementia. It makes intuitive sense, doesn’t it? Patients with A-Fib lose 15%-30% of their heart’s ability to pump blood to their brain, and to the rest of their body. (See: Increased Dementia Risk Caused by A-Fib: 20 Year Study Findings)

Research confirms that older adults with dementia had significantly reduced blood flow into the brain compared with older adults with normal brain function or young adults.

Research Reveals: Anticoagulants Reduce Risk of Dementia

A Swedish study investigated the effect of anticoagulation on the development of dementia among A-Fib patients. Research data was collected on patients diagnosed with and treated for A-Fib in Sweden between 2006-2014. This included 444,106 patients, and over 1.5 million patient-years.

The retrospective registry study compared the incidence of dementia developed in A-Fib patients with and without ongoing anticoagulation with warfarin or direct oral anticoagulation (DOAC) (i.e. dabigatran, rivaroxaban, apixaban and edoxaban).

This study of A-Fib patients found that anticoagulant treatment was associated with a 29% reduced risk of dementia. There was no difference in dementia risk between patients treated with warfarin and those treated with direct oral anticoagulants. 

The authors concluded that the risk of dementia is higher among A-Fib patients not treated with anticoagulation.

In fact, absence of anticoagulation treatment was among the strongest predictors for dementia along with age, Parkinson’s Disease, and alcohol abuse.

Anticoagulants May Reduce Micro-Clots

This study did not tell us how anticoagulation achieves this effect.

Some speculate that anticoagulants, while preventing macro-clots (strokes), also prevent or reduce micro-clots and smaller ischemic events which damage the brain over time.

Another Reason to Not Live with A-Fib

This study also raises another reason not to live in A-Fib if at all possible. Unlike macro-clots which cause strokes and which can kill or severely disable, A-Fib tends to produce micro-clots (smaller ischemic events or silent mini-strokes). The effect of micro-clots may not even be noticeable but, nonetheless, damages our brains over time.