Long-term warfarin use could lead to higher dementia risk

06 May 2016

Heart rhythm disorder might pre-dispose people to a higher risk of developing dementia - and the quality of the drug treatment might play a role, a new study suggests.

Atrial fibrillation could increase the risk of dementia as it exposed patients to both large and small clots that could affect brain function.

According to researchers, patients on the clot-preventing drug warfarin showed a higher dementia risk if their blood levels of the medication were frequently too high or too low.

But not only people with atrial fibrillation ran the risk from the drug, but also those using warfarin for other reasons.

Dr Jared Bunch, the lead researcher, said the findings uncovered two potential concerns - people with atrial fibrillation might face an increased risk of dementia, independent of warfarin use, but warfarin might also contribute to dementia if the doses were not  optimal.

"If people's levels of warfarin were erratic, their dementia risk was higher, whether they had AF or not," said Bunch, who was scheduled to present his findings yesterday at the Heart Rhythm Society's annual meeting, in San Francisco, HealthDay reported.

The results did not prove that either atrial fibrillation or warfarin were to blame, said Bunch, a cardiologist at Intermountain Medical Center, in Murray, Utah.

He added, however, that there was reason to believe that both could contribute to dementia - in part because of effects on blood flow to the brain.

The study involved more than 10,000 patients treated long-term with the blood thinner, warfarin.

A total of 10,537 patients aged 18 years and older, with no history of dementia were involved in the study. They had been treated with the blood thinner for atrial fibrillation and non-AF conditions like valvular heart disease and thromboembolism on a long-term basis.

Other variables including age, hypertension, diabetes, hyperlipidemia, renal failure, smoking history, prior myocardial infarction or cerebral vascular accident, and heart failure were also studied.

A follow-up approximately seven years later revealed that all types of dementia increased in the atrial fibrillation group more than the non-AF group.

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