In addition to an increased incidence of stroke, atrial fibrillation (AF) is also linked with an elevated risk of dementia. A retrospective registry study published in the European Heart Journal now reports that oral anticoagulation therapy can protect against dementia in patients with AF.

Although anticoagulation agents are frequently used to protect against the formation of stroke-inducing large emboli in patients with AF, their effectiveness in protecting against smaller emboli that might result in cognitive decline is less clear. Ideally, a randomized, placebo-controlled trial should be performed to answer this question, but as the study investigators point out, “such a study will never be done due to ethical reasons; it is not possible to treat AF patients at risk of stroke with placebo”. Therefore, they performed a retrospective cohort study to compare the incidence of dementia in patients with AF from a Swedish register.

Among all the patients with AF included in the analysis, 241,160 (54.3%) did not receive oral anticoagulant therapy, 190,570 (42.9%) received warfarin, 12,916 (2.9%) received non-vitamin K oral anticoagulants, and 199 (0.04%) received phenprocuomon. The incidence of dementia in patients treated with anticoagulants was lower than in patients who did not receive anticoagulants (1.14 versus 1.78 per 100 patient-years; P < 0.001). Propensity score matching showed that patients receiving anticoagulants had a 29% lower risk of dementia than patients not receiving anticoagulants (HR 0.71, 95% CI 0.68–0.74).

“Early initiation of anticoagulant treatment in patients with AF could be of value to preserve cognitive function,” conclude the investigators. Additional registry studies are needed to corroborate these findings.