Patients with atrial fibrillation taking long-term warfarin had higher rates of dementia  than non-atrial fibrillation patients, a study presented at the Heart Rhythm Society’s 37th Annual Scientific Sessions has found. 

Atrial fibrillation is thought to increase the risk of dementia from the exposure to both small and large clots that can affect brain function. Anticoagulants used to prevent clots and strokes can increase the risk of bleeding in the brain that can also impact brain function over time. 

Researchers from Intermountain Medical Center Heart Institute, Salt Lake City, UT, included a total of 10,537 patients aged ≥18 years with a no history of dementia prior to study initiation. They were administered a long-term anticoagulant for atrial fibrillation and other conditions such as valvular heart disease and thromboembolism. 

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During the approximate 7-year follow-up period, higher rates of dementia, Alzheimer’s disease, and vascular dementia were seen in atrial fibrillation patients vs. non-atrial fibrillation patients. For both patient groups, the risk of dementia grew as time in the therapeutic range decreased or became more erratic. Warfarin levels that were too high or too low correlated to increased dementia whether patients were receiving a blood thinner or not. 

Patients aged <70 years seemed to be most susceptible to the risk of dementia, the study authors noted.

Overall, patients with atrial fibrillation consistently exhibited higher rates of all types of dementia despite the adequacy of anticoagulation. Findings support the notion that the treatment efficacy was strongly associated with dementia. 

T. Jared Bunch, MD, lead author, described the study data to be the first to demonstrate significant cognitive risk factors for patients treated with warfarin long-term regardless of the indication for anticoagulation. “In this regard, only those that absolutely need blood thinners should be placed on them long-term,” he added. 

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