Atrial fibrillation (A-fib) is the most common form of heart arrhythmia - or irregular heartbeat - and it can sometimes cause more serious heart conditions, such as blood clots, stroke, and even heart failure.
The American Heart Association (AHA) estimate that, in the United States, there are around 2.7 million adults currently living with A-fib. The AHA also report that if left untreated, A-fib can double a person's chances of heart-related deaths and increase the risk of stroke by up to fivefold.
A new, large-scale study connects the two conditions. Researchers at the Intermountain Medical Center Heart Institute in Salt Lake City, UT, investigate the link between dementia rates and the timeframe for administering blood thinners - a common form of treatment for patients with A-fib.
The findings were presented at Heart Rhythm 2017, the Heart Rhythm Society's 38th Annual Scientific Sessions, held in Chicago, IL.
Studying the link between anticoagulation treatment and dementia risk
The researchers analyzed more than 76,000 patients with A-fib who had no history of dementia and who received treatment with anticoagulants such as antiplatelets or warfarin. The study followed these patients from the moment they were diagnosed with A-fib to the beginning of their anticoagulation treatment.
Then, the participants were divided into two groups: those who started the blood thinning treatment immediately (in under 30 days from the diagnosis), and those who received the treatment later (a year after the initial diagnosis).
Of all the patients, a total of 26,189 ultimately received a blood thinner, with 21,781 patients receiving an antiplatelet and 4,408 being administered warfarin as anticoagulation treatment.
Blood thinners are commonly prescribed to prevent stroke, but sometimes physicians delay prescribing them due to various reasons, including a low risk of stroke.
As a result, the team also used a prediction tool called the CHADS2 Vasc score to determine the risk of stroke among the participants.
A delay as little as 30 days could increase dementia risk
The researchers found a significant increase in the risk of dementia among patients whose treatment was delayed.
Patients with a low risk of stroke who received delayed treatment had a 30 percent higher risk of dementia than those who received treatment immediately. Patients at a high risk of stroke who received delayed treatment had a 136 percent higher chance of developing dementia.
Additionally, the study revealed a linear risk of stroke that increased with the number of days that the treatment was delayed for. Specifically, the delay was broken down into the following time periods: under 30 days, 31 days to a year, 1 to 3 years, and finally, more than 3 years.
Dr. Jared Bunch, director of heart rhythm research at the Intermountain Medical Center Heart Institute, comments on the findings:
"Our results reinforce the importance of starting anticoagulation treatment as early as possible after a patient is diagnosed with atrial fibrillation. We saw for the first time that waiting even just 30 days to initiate anticoagulation treatment can increase a patient's long-term risk of developing dementia.
We want to ensure we're doing everything possible to limit the risk of brain injury for our patients. In this study, the benefit was derived from using warfarin, and we hope newer anticoagulants that perform better than warfarin and are easier to start and use will further improve dementia risk."
The researchers at the Intermountain Medical Center Heart Institute are currently working on a large-scale prospective study that compares a newer anticoagulant called dabigatran with warfarin, and monitors cognitive decline over a period of 2 years.