Findings of a new study have revealed a link between long-term use of the blood thinner warfarin and higher rate of dementia in patients with heart rhythm disorder atrial fibrillation.
Researchers from the Intermountain Medical Center Heart Institute looked at over 10,000 patients treated with warfarin, a drug that helps reduce, treat or prevent the formation of blood clots to cut risks for stroke and heart attack.
The drug is prescribed to patients with atrial fibrillation, the most common form of arrhythmia, a condition marked by problematic heartbeats that are too fast or too slow, sometimes with irregular rhythm.
For their study presented at the Heart Rhythm Society's 37th Annual Scientific Sessions, lead author T. Jared Bunch and colleagues found that patients with atrial fibrillation who were treated with the anticoagulant had higher rates of dementia compared with their anticoagulated counterparts without atrial fibrillation.
Dementia, a neurological disorder that affects the memory and cognitive abilities, is now among the top causes of ill health and death in developed countries. Alzheimer's disease is the most prevalent of this condition.
The researchers found that patients taking warfarin had higher risk for dementia when levels of the drug were consistently too high or too low, and this was observed regardless of why the person receives the blood thinner.
"Our study results are the first to show that there are significant cognitive risk factors for patients treated with warfarin over a long period of time regardless of the indication for anticoagulation," Bunch said.
Bunch said that the study suggests that people with AF may have increased risk for dementia whether or not they use warfarin. Atrial fibrillation puts them at risk for the neurological disorder, as it exposes them to both small and large clots that may impact brain function.
Warfarin contributes to the development of dementia if the doses given are not optimal. Patients with erratic warfarin levels are prone to blood clots and strokes. This is why they need to undergo regular blood tests to ensure their warfarin level is in the "therapeutic range," high enough to prevent blood clots and low enough to prevent brain bleeds that can negatively affect brain function over time.
"Anticoagulation clearly has a role as far as long-term brain health and viability," Bunch said. "We learned as well that AF is an additive disease state, in that it increases risk beyond anticoagulation, so its management also becomes very important to lower dementia risk."