For patients with atrial fibrillation >65 years old, oral anticoagulant treatment was associated with a lower risk for dementia than patients not receiving oral anticoagulant treatment, according to a study published in the European Heart Journal.

Researchers of this retrospective study analyzed data from the Swedish Patient Register and the National Dispensed Drug Register to assess if the oral anticoagulant treatment provided brain protection to patients with atrial fibrillation, regardless of stroke risk. The Swedish Patient Register was used to obtain information about patients on past and current disease diagnoses, stroke risk score, previous strokes and ischemic attacks, hypertension, heart failure, diabetes, vascular disease, age, and sex.

The National Dispensed Drug Register was used to obtain information about medications used at baseline and the quantities and dispensing intervals for oral anticoagulants. The first 30 days postdiagnosis was considered the baseline period, and follow up continued until death, emigration, or the end of the study.

Of the 91,254 patients included in the study, 43% were on oral anticoagulant treatment at baseline. After propensity score matching, 23,746 patients were included in each cohort. The oral anticoagulant cohort was 30.7% women, had a mean age of 61.5 years old, and had a mean CHA2DS2-VASc score of 0.91. The nonoral anticoagulant cohort was 29.9% women, had a mean age of 60.8 years old, and had a mean CHA2DS2-VASc score of 0.88.

Overall, 956 patients were diagnosed with dementia, and oral anticoagulant treatment was associated with a lower risk when compared with patients not taking oral anticoagulants (subhazard ratio 0.62; 95% CI, 0.48-0.81).

This benefit was even more pronounced in patient with a CHA2DS2-VASc score of 1 (hazard ratio [HR] 0.57; 95% CI, 0.43-0.74).

The composite brain health end point of ischemic or hemorrhagic stroke or dementia was 12% lower (HR 0.88; 95% CI, 0.77-1.00) in the oral anticoagulant cohort and was most beneficial in patients >65 years old while being potentially harmful in patients <60 years old.

Limitations of this study include the lack of randomization, hidden confounding variables, an inability to assess adherence to medication usage, and potential uncoded or low sensitivity for early detection of dementia.

The researchers concluded that “[m]en and women with [atrial fibrillation] and CHA2DS2-VASc score 0 or 1 who use [oral anticoagulants] appear to have lower risk of dementia than those who do not use [oral anticoagulants]. In a composite [end point] of dementia, ischaemic stroke, and [intracerebral bleedings], there was a benefit of anticoagulants in patients 65 years and older.”

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Two researchers report associations with pharmaceutical companies. Please see the original reference for a full list of authors’ disclosures.

Reference

Friberg L, Andersson T, Rosenqvist M. Less dementia and stroke in low-risk patients with atrial fibrillation taking oral anticoagulation [published online May 16, 2019]. Eur Heart J. doi: 10.1093/eurheartj/ehz304