Study paints a more complete picture of bleeding risk with stroke prevention drugs

People with atrial fibrillation, a kind of irregular heartbeat, take oral anticoagulants (blood thinners) to reduce their risk of stroke. These drugs are highly effective, however they can increase the risk of bleeding.

While brain bleeding is a well-recognized and important risk, new research published in Circulation suggests that bleeding outside the brain is common and should be more carefully considered.

The study, led by Dr. Deborah Siegal of The Ottawa Hospital and the University of Ottawa, analyzed records from more than 73,000 people with atrial fibrillation who participated in five clinical trials of oral anticoagulants. The analysis showed that over two years, one in four experienced clinically relevant bleeding outside the brain. 

While the majority of these bleeding events were not considered “major”, they can still have consequences. 

“Stroke prevention remains the top priority for patients with atrial fibrillation, but our findings highlight an important part of the patient experience that has received less attention,” says Dr. Deborah Siegal, scientist and hematologist at The Ottawa Hospital, associate professor at the University of Ottawa and Tier 2 Canada Research Chair in Anticoagulant Management of Cardiovascular Disease. 

“Even when bleeding outside the brain is not considered ‘major,’ it is common and can disrupt daily life, lead to hospital visits and affect overall well-being. Further research is needed to better understand the consequences of these common but less severe bleeds for patients and develop strategies to reduce this bleeding while preserving the benefits of stroke prevention.”

The study also revealed that low hemoglobin, impaired kidney function, prior stroke, cancer and Asian ancestry were among the strongest predictors of clinically relevant bleeding outside the brain. However, known clinical factors only accounted for about two thirds of overall bleeding risk, suggesting other, not yet understood factors are also at play.