Delaying anticoagulation treatment for atrial fibrillation increases dementia risk, study suggests

Results reinforce the importance of starting anticoagulation treatment as soon as possible after diagnosis, researchers conclude.

warfarin blood thinner for atrial fibrillation

Delaying anticoagulation treatment in patients with atrial fibrillation may increase the risk of dementia, according to a new study.

Researchers at the Intermountain Medical Center Heart Institute in Salt Lake City, in the US, studied more than 26,189 patients with atrial fibrillation with no previous history of dementia, finding the longer treatment was delayed the higher the risk of cognitive decline.

There was a 30% higher risk of dementia in low-risk patients who did not start treatment with an antiplatelet or warfarin until a year after a diagnosis of atrial fibrillation compared with those who started treatment in the first month. In high-risk patients, the chance of dementia was 136% higher in those who had delayed treatment.

“Our results reinforce the importance of starting anticoagulation treatment as early as possible after a patient is diagnosed with atrial fibrillation,” said study leader Jared Bunch, director of heart rhythm research at the Intermountain Medical Center Heart Institute.

“We saw for the first time that waiting even just 30 days to initiate anticoagulation treatment can increase a patient’s long-term risk of developing dementia.”

The research was presented at the Heart Rhythm Society annual conference in Chicago on 12 May 2017.

Of the 26,189 patients involved in the study, 21,781 received an antiplatelet and 4,408 warfarin. Aspirin or warfarin was started in the first 30 days in 43.6% of the patients.

The researchers, who said the study was the first of its kind, also found that there was a linear relationship between risk of dementia and the length of time before anticoagulant treatment was initiated.

Reasons for delays in treatment after a diagnosis of atrial fibrillation include a low risk of stroke, use of other treatment options like aspirin, older age, and multiple comorbidities, they said.

Bunch added: “We want to ensure we’re doing everything possible to limit the risk of brain injury for our patients, and our study not only shows the importance of early therapy, but also shows the very limited role, if any, of aspirin for stroke prevention.”

The team is now planning further research into the impact of cognitive changes with the newer anticoagulant drugs, such as dabigatran.

Commenting on the study, Rosa Sancho, head of research at Alzheimer’s Research UK, said: “Atrial fibrillation has previously been linked with an increased risk of dementia, and these new results indicate that delays in treating atrial fibrillation may increase dementia risk.

“With no currently available treatments able to slow or halt dementia in its tracks, treating other conditions that can alter dementia risk is of key importance.”

 She said doctors had to weigh up the risks and benefits for individual patients.

“These results highlight the link between the timeliness of treating atrial fibrillation and dementia risk, but this will need to be explored in future studies to ensure doctors can make fully informed decisions about how best treat conditions such as atrial fibrillation,” she concluded.

Last updated
The Pharmaceutical Journal, May 2017;Online:DOI:10.1211/PJ.2017.20202745