Warfarin Versus Aspirin for Prevention of Cognitive Decline in Atrial Fibrillation: Randomized Controlled Trial (Birmingham Atrial Fibrillation Treatment of the Aged Study)

Study Questions:

Does anticoagulation prevent cognitive dysfunction in elderly patients with atrial fibrillation (AF)?


The subjects of this study were 973 patients 75 years or older (mean age 81.5) with AF. They were randomly assigned to treatment with warfarin (n = 488, dose adjusted to maintain international normalized ratio 2-3) or aspirin (n = 485, 75 mg/day). Cognitive function was measured with the Mini-Mental State Examination at 9, 21, and 33 months of follow-up. Patients who had a stroke were censored from the analysis.


There were no significant differences in the Mini-Mental State Examination scores between the warfarin and aspirin groups. The scores were not significantly lower at 33 months than at 9 months in either group.


the authors concluded that compared to aspirin, warfarin does not provide more protection from cognitive decline over 33 months in elderly patients with AF.


Some studies have reported that AF is associated with cognitive decline even in the absence of clinically manifest stroke. A protective effect against silent strokes could explain this finding. Although warfarin clearly is superior to aspirin for prevention of stroke in patients with AF, the results of the present study suggest warfarin may not be superior to aspirin for protection against silent strokes, at least over 33 months of follow-up. Because the study understandably did not include a control group treated with placebo, it is unknown whether warfarin and aspirin were equally effective in preventing cognitive dysfunction, or whether cognitive function would have remained stable even in the absence of treatment with either agent.

Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Anticoagulation Management and Atrial Fibrillation, Atrial Fibrillation/Supraventricular Arrhythmias

Keywords: Cognition, Stroke, Platelet Aggregation Inhibitors, Warfarin, Atrial Fibrillation

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