Overtreatment of Atrial Fibrillation Patients Using Antiplatelet Agent Associated with Long-term Risk of Dementia

CHICAGO – Atrial fibrillation patients diagnosed with Coronary Artery Disease who take anticoagulation drugs like warfarin, along with aspirin, increase their risk of developing dementia if the medications are not properly managed, according to a new study from the Intermountain Medical Center Heart Institute.

Atrial fibrillation is an abnormal heart rhythm, which raises the risk of stroke and places the patient at higher risk of developing all forms of dementia. However, the specific mechanisms behind the association of atrial fibrillation and dementia are unknown. Results of the study were presented during the American Heart Association Scientific Sessions in Chicago on Sunday, November 16.

“Atrial fibrillation patients, who have also been diagnosed with coronary artery disease, are often prescribed a dual-drug regimen as part of their treatment – an anticoagulation drug like warfarin, and an antiplatelet drug like aspirin – in an effort to reduce their risk of stroke as well as future heart attacks,” said Jared Bunch, MD, lead author of the study and director of electrophysiology at the Intermountain Medical Center Heart Institute in Murray, Utah. “The results of our study highlight the potential harms of the blood thinners used to reduce the risk of stroke particularly in the presence of other blood thinning agents, and stress the importance of closely monitoring a patient’s use of such medications to reduce the risk of developing dementia.”

More than 1,000 atrial fibrillation patients with no history of dementia were studied for up to 10 years while on the dual-drug regimen. Once adjusted for various risk factors, patients who had abnormally slow blood clotting times from their treatment with warfarin– meaning they were receiving too much medication – on 25 percent or more of their monitoring tests were more than twice as likely to be diagnosed with dementia than patients whose tests showed overtreatment less then 10 percent of the time.

Four years ago, researchers from the Intermountain Medical Center Heart Institute found that patients with atrial fibrillation had much higher rates of all forms of dementia, including Alzheimer’s disease. This discovery lead researchers to further explore associations with atrial fibrillation treatments and causes of dementia.

Earlier this year, a study concluded that atrial fibrillation patients who were on blood-thinning medications like warfarin were at a higher risk of developing dementia if their doses were not in the optimal recommended range. This new study built on that finding by examining data on atrial fibrillation patients using the dual-drug regimen.

“Many heart patients may be taking aspirin on a regular basis with the understanding it is beneficial to their heart health,” said Dr. Bunch. “However, atrial fibrillation and heart disease patients taking warfarin and aspirin should check with their doctor regularly to evaluate the need for the continued use of both medications, or explore other anti-clotting drugs or devices to reduce their risk of developing dementia. Also for people who do not have a need for aspirin and use it because it may help their heart health should not use it unless directed by their doctor.”

The next step in further evaluating risks of atrial fibrillation treatments and dementia is to conduct a prospective study looking at safer anticoagulation drugs and their impact on cognition and memory function using cranial imaging. It would include exploring genetic markers as well.

Other members of the Intermountain Medical Center Heart Institute team include Heidi T. May, Ph.D.; Tami L. Bair, R.N.; Victoria Jacobs, N.P.; Brian G. Crandall, M.D.; J. Peter Weiss, M.D.; Jeffrey S. Osborn, M.D.; Charles Mallendar, M.D.; John D. Day, M.D.; Jeffrey L. Anderson, M.D.; Jeffrey L. Olson, M.D.; Katie Johanning, PharmD; Yenh Long, PharmD; Scott M. Stevens, M.D.; and Scott C. Woller, M.D.