Blood thinners promise reduction in dementia risk

Published in the European Heart Journal, the study ‘Less dementia with oral anticoagulation in atrial fibrillation’, analysed the health record data of 444,106 AF patients in Sweden and found that patients using anticoagulants to treat AF reduced their risk of dementia by up to 48 percent compared to those with the same condition not taking the medication.

Lead author of the paper, Cardiologist and Associate Professor Leif Friberg says that after years of researching, the results did not come as a surprise.

“I have been doing research on atrial fibrillation and stroke for many years and knew that the very common heart arrhythmia is associated with a 40 percent increased risk of dementia,” he says.

“We know for a fact that atrial fibrillation causes dementia… [and] considering that 12-15 percent of 75 year olds have this arrhythmia, and even more at higher ages, the problem is significant to say the least.

“[The results] rather confirmed our hypothesis… it was good news if at least some dementia can be averted by treatment.”

The anticoagulant medication prescribed to AF patients works to prevent blood clots travelling from the heart to the brain where they get stuck in narrow vessels where they stop blood flow causing brain infarction or stroke.

Oral anticoagulant drugs, like warfarin or the newer ‘non-vitamin K oral anticoagulants’ (NOAC) drugs are ‘highly efficient’ in preventing the formation of these large blood clots and offer at least a 70 percent risk reduction.

While Dr Friberg says their study can’t claim to prove causal relationships, he feels the team are on unusually firm ground with these results.

Associate Professor Michael Woodward, Chief Medical Advisor in Victoria, Dementia Australia, has welcomed the research results and says they are ‘absolutely interesting’.

“It’s exciting that this research is being done,” he says.

“I think it is a great outcome from a great study and is what we expect.

“This discovery offers an opportunity to reduce the risk of dementia while we wait and are working on a treatment.”

Dr Friberg adds that more research needs to be done and welcomes other researchers to conduct their own study.

“I would like to see research teams in other parts of the world reproduce our study,” he says.

“Confirmatory evidence from other populations would increase the strength of our findings.

“I definitely think our study is important in this context and that it also brings some hope.”

From the research findings, Dr Friberg says it may be necessary to start anticoagulant treatment earlier.

“The stroke risk in young and otherwise healthy patients with atrial fibrillation is so low that recommendations often result in postponement of treatment until patients are in their 70s,” he says.

“We don’t know yet which is the right time to start treatment to prevent dementia – it may be much earlier than now.

“An even more important consequence has to do with endurance on anticoagulant treatment.

“We are pretty good at initiating anticoagulant treatments for stroke prevention when patients present with atrial fibrillation but people drop out of treatment over time.

“Better awareness of what is at stake would probably lead to fewer dropping out of treatment.”

Dr Woodward adds that increasing evidence suggests that the best things to do to reduce risk of dementia is improve your lifestyle by keeping active socially, mentally and physically, maintaining a healthy and balanced diet and controlling cardiovascular risk.