Blood-thinning medication linked to slower cognitive decline
People with both atrial fibrillation and Alzheimer’s disease who are treated with modern NOAC blood-thinning medicines may experience a slower rate of cognitive decline. This is shown by a study from Karolinska Institutet published in the European Heart Journal.
Atrial fibrillation is a common heart rhythm disorder among older people, including many with Alzheimer’s disease. The condition is often treated with blood-thinning medication to reduce the risk of blood clots. Previous studies suggest that anticoagulant treatment may lower the risk of developing dementia, but its impact in patients with established Alzheimer’s disease is less well understood.
“There are reasons to believe that the treatment could have a positive effect on cognition, for example by improving blood flow and reducing small-scale damage in the brain,” says Maria Eriksdotter, professor at the Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, and senior consultant in geriatric medicine at Karolinska University Hospital, who led the study.
Could make a difference over time
The study is based on data from the national quality register SveDem (Swedish Register for Cognitive Disorders/Dementia) and includes 7,308 people with both atrial fibrillation and Alzheimer’s disease. The participants were divided into three matched groups: those treated with newer anticoagulants known as NOACs, those receiving the older anticoagulant warfarin (Waran), and those not using any anticoagulant medication. The researchers monitored the participants’ cognitive function over time using the standardised Mini-Mental State Examination (MMSE).
The results showed that people treated with NOACs experienced a significantly slower decline in cognitive function compared with those receiving warfarin or no anticoagulant treatment. The difference corresponded to just over 0.2 MMSE points per year.
“The difference is modest for an individual patient from one year to the next, but over a longer period even such an effect could influence how cognitive function develops. Our findings suggest that NOAC treatment may also be significant for cognition in this patient group,” says Nanbo Zhu, researcher at the same department.
Lower risk of other health problems
People treated with NOACs also had a lower risk of death, stroke, blood clots and fractures compared with those who did not receive anticoagulant treatment. Warfarin was likewise associated with a lower risk of death, stroke and blood clots, but with a higher risk of major bleeding.
The researchers note several limitations of the study. As this is an observational study, it cannot establish cause and effect with certainty. Some factors that may influence both treatment choice and health outcome could not be fully analysed. In addition, some patients may have switched between different medications during the follow-up period.
The study was funded by, amongst others, the Swedish Research Council, the Swedish Brain Foundation, CIMED, ALF project funding and Karolinska Institutet funds. Maria Eriksdotter has participated as a consultant in one-off meetings with BioArctic AB, Roche, Eli Lilly, Biogen/Eisai and Novo Nordisk, and has given lectures at symposia sponsored by Roche and BioArctic/Eisai. No other conflicts of interest are reported.
Publication
“Oral anticoagulants, cognition, and clinical outcomes in atrial fibrillation and Alzheimer’s disease: a Swedish nationwide study”, Nanbo Zhu, Hong Xu, Sara Garcia-Ptacek, Sumonto Mitra*, Maria Eriksdotter*, European Heart Journal, online August 12, 2026, doi: 10.1093/eurheartj/ehag584.
*shared last authorship