Overtreatment of Atrial Fibrillation Can Double Dementia Risk

HealthDay News — Overtreatment of atrial fibrillation with anticoagulants may double the risk of dementia, according to a new study being presented at the annual meeting of the American Heart Association, held from Nov. 15 to 19 in Chicago.

Thomas Jared Bunch, MD, director of electrophysiology at the Intermountain Heart Institute in Murray, Utah, and colleagues studied 1,031 patients with no history of stroke or dementia who were taking warfarin combined with antiplatelet therapy with aspirin or clopidogrel to prevent stroke.

Over 10 years of follow-up, the researchers found that patients taking the combination of drugs who had abnormally slow clotting times (International Normalized Ratio measurement above 3) 25% or more of the time were more than twice as likely to develop dementia as patients whose clotting time remained in normal ranges more than 90% of the time. Patients who had abnormally slow clotting times were receiving too much medication, Bunch explained. The increased risk was higher than what was found in a study of warfarin alone, he added.

“In patients with atrial fibrillation, dementia risk is dependent on the efficacy and control of long-term use of anti-clotting drugs,” Bunch told HealthDay.


  1. Long-term overtreatment with anti-clotting/antiplatelet drug combo may raise risk of dementia in people with irregular heartbeat [news release]. Chicago: American Heart Association. Available at: http://newsroom.heart.org/news/long-term-overtreatment-with-anti-clottingantiplatelet-drug-combo-may-raise-risk-of-dementia-in-people-with-irregular-heartbeat. Accessed November 17, 2014.