Atrial fibrillation may accelerate cognitive decline in women

Atrial fibrillation (AF) appears to contribute to an increased risk of rapid progresssion to mild cognitive impairment (MCI) and dementia in women, as reported in a study.

Large data from the National Alzheimer’s Coordinating Center (NACC) cohort showed that women with AF had threefold greater odds of MCI (odds ratio [OR], 3.00, 95 percent confidence interval [CI], 1.22–7.37) and dementia (OR, 3.43, 95 percent CI, 1.55–7.55) compared with AF-free women. [Alzheimers Dement 2023;doi:10.1002/alz.13060]

In men, on the other hand, AF showed no significant association with either MCI or dementia.

Further analysis showed that women with AF and normal cognition at baseline were at increased risk of progression to MCI (hazard ratio [HR], 1.26, 95 percent CI, 1.06–1.50), while women with AF and MCI at baseline were at increased risk of progression to vascular dementia (HR, 3.27, 95 percent CI, 1.89–5.65) relative to men with AF or men and women without AF.

“The analyses indicate stronger associations between AF and declining cognitive function in women compared with men,” said lead study author Dr Kathryn Wood of Emory University, Atlanta, Georgia, US.

The role of silent strokes

AF is the most common heart rhythm disorder, affecting more than 40 million people worldwide. How AF may raise the risk of MCI and dementia may have to do with the association of AF with a more than twofold risk of silent strokes. Silent strokes, in turn, can cause small injuries to the brain that can add up over time and lead to cognitive impairment. [Europace 2018;20:1399-1421]

Wood recognized the potential clinical implications of their findings, saying that healthcare providers frequently dismiss or associate AF symptoms in women with stress or anxiety, leading to prolonged periods without diagnosis, whereas men tend to receive swifter diagnosis and treatment.

“European Society of Cardiology Guidelines for the care of patients with AF recommend oral anticoagulants for both women and men. [As such], being undiagnosed means not receiving oral anticoagulant medication to prevent blood clots and strokes caused by AF,” Wood explained. [Eur Heart J 2021;42:373-498]

“These [undiagnosed] women may be having clots that go to small blood vessels in their brain, causing them to lose brain function gradually and develop cognitive impairment,” she continued.

For the study, Wood and her team looked at 43,630 individuals (average age 78.5 years, 46 percent women) from the NACC cohort who had at least three annual clinic visits during which they took neuropsychological tests and were grouped into three, as follows: normal cognition, MCI, or dementia. Of the participants, 4,593 (11 percent) had AF at baseline.

Over a median follow-up of 4 years, 30 percent of participants progressed to a worse stage of cognitive impairment and 21 percent received a diagnosis of dementia.

Wood underscored the need to establish ways to identify AF patients at the highest risk of cognitive decline and stroke that will inform future interventions to prevent or slow the progression to cognitive impairment and dementia.