Patients with the common heart rhythm disorder atrial fibrillation who don’t take blood thinners that reduce the risk of stroke are also at higher risk for dementia and death, a large UK study shows.
Atrial fibrillation, or Afib, increases a patient’s risk of developing blood clots in the heart that can break off, travel to the brain, and cause a stroke.
The blood thinners used to prevent those clots come with their own risks of serious bleeding, so doctors sometimes hold off on prescribing them for patients thought to be at a relatively low risk of a stroke.
But stroke may not be the only outcome to worry about, the research team found.
Even Afib patients with a low risk of stroke may face an elevated risk of so-called vascular dementia, cognitive problems caused by impaired blood flow to the brain, they wrote on Wednesday in Nature Medicine.
Researchers tracked 36,340 primary care patients with a diagnosis of Afib, no history of stroke, a low perceived risk of stroke based on clinical risk factors and who were not prescribed oral anticoagulants such as Eliquis from Bristol Myers Squibb and Pfizer. They were compared with 117,298 similar patients without Afib.
With half the patients followed for at least 5 years, and after accounting for individual risk factors, rates of first strokes and of blood clots in arteries were each more than 100% higher in the untreated Afib patients. This group also had a 44% higher risk of death during the study, and a 68% higher risk of developing vascular dementia.
The study was not designed to prove that untreated Afib caused these outcomes, the researchers noted.
Randomized controlled trials are needed to determine whether these “low stroke risk” patients with Afib “could benefit from earlier use of oral anticoagulants to improve their prognosis and prevent cognitive decline,” they said.
A separate study of 1,657 Afib patients published on Thursday in Blood Advances by a different team of researchers found that trying to limit the bleeding risks associated with blood thinners by prescribing a lower-than-usual dose is likely to backfire.
“Patients with Afib who took low doses of blood-thinning medications known as direct oral anticoagulants experienced more bleeding episodes during the first three months of treatment… compared with similar patients who took standard doses of the same medications,” the researchers reported.
Commonly used blood thinners for this patient population include Eliquis and Xarelto from Bayer and Johnson & Johnson.
