Patients with a common heart rhythm disorder are at risk of vascular dementia

Patients with atrial fibrillation (AF), the most common heart rhythm disorder, have a higher than expected risk of developing some forms of dementia, a new study has found.

AF is known to be associated with strokes and blood clots in older patients and those with other health conditions. These groups of patients are typically given blood thinners (anticoagulants) as prevention therapy, but younger individuals or those perceived as ‘low-risk’ do not.

In this study, researchers from the University of Birmingham looked at patients with AF who would not normally be prescribed blood thinners. The findings are published in a new article in Nature Medicine, assessing electronic healthcare records from more than 5 million primary care patients across the UK. The study was funded by the National Institute for Health and Care Research (NIHR) and supported by the NIHR Birmingham Biomedical Research Centre (BRC).

“This study demonstrates a clear correlation between AF and vascular dementia. This may have a similar mechanism to the association between AF and stroke.”

Alastair Mobley, PhD researcher

The team focused on more than 36,000 patients aged 40-75 years who had a diagnosis of AF, no history of stroke, a low risk of stroke based on clinical scores, and no prescription of anticoagulants. During an average follow-up period of 5 years, they were compared with over 100,000 patients without AF but matched for the same age, sex and region.

Despite being in this ‘low-risk’ group, the patients with AF had double the chance of developing a stroke or major blood clot than those without AF. There was a 17% increased risk of developing dementia due to any cause, and a 68% higher chance of vascular dementia in patients with AF. More patients with AF also died during their follow-up (44% higher risk).

Dipak Kotecha, Professor of Cardiology at the University of Birmingham, co-lead of the NIHR Birmingham BRC’s Thrombo-Inflammation research theme, and senior author of the study said:

“Atrial fibrillation is one of the most common heart conditions, with over 60 million cases expected worldwide by 2050. With its prevalence continuing to rise, it is crucial that we develop strategies to prevent not only stroke, but outcomes like dementia which are a big concern for patients and healthcare systems. Our research highlights the urgency of addressing AF comprehensively, considering its overall impact on the wellbeing of patients”.

Alastair Mobley, a PhD researcher at the University of Birmingham, researcher at the NIHR Birmingham BRC, and first author of the study said:

“This study demonstrates a clear correlation between AF and vascular dementia. This may have a similar mechanism to the association between AF and stroke. Ongoing clinical trials such as DaRe2THINK, currently being run by the University of Birmingham, are exploring whether blood thinners in lower-risk patients can provide a way to prevent these bad outcomes.”