https://immattersacp.org/weekly/archives/2017/10/31/1.htm

Early oral anticoagulation in afib may protect against dementia

Taking anticoagulant treatment at baseline was associated with a 29% lower risk of dementia than not receiving anticoagulant treatment and a 48% lower risk when analyzed on treatment.


Patients with atrial fibrillation (AF) who are taking oral anticoagulants have lower risk of dementia than those not on anticoagulation, a study found.

To compare the incidence of new dementia in patients with atrial fibrillation with and without oral anticoagulants, and to explore if there was a difference on this outcome between direct oral anticoagulants and warfarin, researchers conducted a retrospective registry study of all patients with AF and no previous diagnosis of dementia in Sweden between 2006 and 2014. Results were published by the European Heart Journal on Oct. 24.

The study included 444,106 patients and over 1.5 million years of risk, during which 26,210 patients received a new diagnosis of dementia (1.73 per 100 years at risk). At baseline, 54.3% of patients were not taking oral anticoagulant treatment, 42.9% used warfarin, 0.04% used phenprocoumon (a long-acting vitamin K antagonist derived from coumarin with similar properties to warfarin), and 2.9% used a direct oral anticoagulant.

Patients who developed dementia were older and had more comorbidity than patients who did not develop dementia. The strongest predictors for dementia were age (hazard ratio [HR] per decade, 2.19; 95% CI, 2.16 to 2.22), Parkinson's disease (HR, 2.46; 95% CI, 2.25 to 2.69), absence of oral anticoagulant treatment (HR, 2.08; 95% CI, 1.73 to 2.53), and alcohol abuse (HR, 1.53; 95% CI, 1.41 to 1.66).

Taking anticoagulant treatment at baseline was associated with a 29% lower risk of dementia than not receiving anticoagulant treatment (HR, 0.71; 95% CI, 0.68 to 0.74) and a 48% lower risk when analyzed on treatment (HR, 0.52; 95% CI, 0.50 to 055). Direct comparison between direct oral anticoagulants and warfarin showed no difference in dementia (HR, 0.97; 95% CI, 0.67 to 1.40).

The benefits of oral anticoagulants appeared to be more pronounced among patients who received early treatment after the first diagnosed AF episode, which suggested a dose-response relationship between unprotected time in AF and development of dementia, the authors noted.

Also, there was a trend toward more benefit from treatment in patients with higher CHA2DS2-VASc scores, which suggests that microembolization might be a cause of dementia in AF patients, the authors noted.

“Our findings regarding dementia protection may provide a second argument for initiation of treatment among untreated AF-patients,” the authors wrote. “Since the time from diagnosis to start of treatment appears to be an independent risk factor, early initiation of treatment is desirable in order to preserve cognitive function.”