A new study from the European Society of Cardiology suggests that blood-thinning drugs used to lower the risk of stroke and heart attack in patients with atrial fibrillation (AF) could also significantly decrease the chances of developing dementia. The breakthrough discovery, published in the European Heart Journal on Tuesday, provides a huge opportunity for at-risk patients to avoid developing dementia — which currently affects over 50 million people worldwide, according to Alzheimer’s Disease International.
The researchers arrived at this conclusion by studying health data from 444,000 Swedish patients with AF, diagnosed between 2006 and 2014. They followed and checked which drugs were prescribed and dispensed to these patients, resulting in a swath of data that is (by adding each patient’s distinct trial time) worth 1.5 million years of follow-up, where some 26,210 patients were diagnosed with dementia at that time.
“As a clinician I know there are AF patients who have a fatalistic view on stroke. Either it happens or it does not. Few patients are fatalistic about dementia, which gradually makes you lose your mind,” co-author Dr. Leif Friberg at the Karolinska Institute in Stockholm, Sweden, said in a statement. “No brain can withstand a constant bombardment of microscopic clots in the long run. Patients probably want to hang on to as many of their little grey cells for as long as they can.”
However the findings could not establish a clear cause and effect between blood thinning drugs (also known as anticoagulants), AF, and dementia. To explicate, they “strongly suggested” that presribed anticoagulants — like warfarin, apixaban, dabigatran, edoxaban and rivaroxaban — protected AF patients against dementia. Experts believe that AF increases the risk of stroke and developing blood clots, which could later end up in the brain and cause dementia.
Dr. Friberg and his colleague, Dr. Mårten Rosenqvist, also acknowledged that their study has other limitations, such as not having an access to the complete medical histories of the patients and details of other diseases, as well as the fact that dementia is an insidious disease because it’s not necessarily immediately diagnosed. In short, the reported cases of dementia could constitute a lower population than reality.
Despite the uncertainty, Dr. Friberg was quick to recommend that AF patients continue taking anticoagulants, or (at least) to start taking them as soon as possible. “Doctors should not tell their patients to stop using oral anticoagulants without a really good reason. To patients, I would say don’t stop unless your doctor says so,” he said. The fact is, taking anticoagulants worked, although more work is needed to better explain the underlying mechanisms behind the effect.
Commenting on the study, which made no distinction between the effectiveness of using the older anticoagulant warfarin and newer pills, Alzheimer’s Research UK head of science Dr. Carol Routledge said “The findings highlight a need to investigate this link further, but the nature of the study prevents us from firmly concluding that anticoagulants reduce the risk of dementia,” she told The Guardian. “It will be important to see the results of other ongoing studies in this area, as well as teasing apart the exact relationship between anticoagulants and the risk of different types of dementia.”