Modern blood-thinning drugs prescribed to millions of patients could help slow down cognitive decline in people living with Alzheimer's disease, Swedish researchers have found.
The tablets are regularly prescribed to more than 1.6 million patients in the UK who suffer from atrial fibrillation, a common heart rhythm disorder. The condition is significantly more common in older adults and individuals who are at risk of dementia or already living with the memory-robbing disease.
Atrial fibrillation occurs when erratic electrical signals affect the rhythm of the heart, interfering with normal blood flow. Alzheimer's disease, the most widespread form of dementia, involves progressive damage to brain cells, gradually degrading memory, language, and motor skills.
In the new study, Swedish researchers concluded that blood-thinning drugs may help slow down cognitive decline in Alzheimer's patients by improving blood flow to the brain. However, they stopped short of recommending the pills for those who do not have atrial fibrillation, noting that the benefits were only observed in patients taking newer types of blood-thinners.
Experts believe the findings could be significant for the roughly one million people in the UK currently living with dementia. That figure is expected to rise to 1.4 million by 2040.
Writing in the European Heart Journal, study lead author Dr Maria Eriksdotter said: "There are reasons to believe that the treatment could have a positive effect on cognition, by improving blood flow and reducing small-scale damage in the brain."
The research was led by experts at Karolinska University Hospital, a major medical institution in Sweden known globally for its clinical research. The European Heart Journal is a leading peer-reviewed publication covering cardiovascular medicine.
The study analysed data from 7,308 people with atrial fibrillation and Alzheimer's, drawn from the Swedish Register for Cognitive Disorders.
Cognitive benefits of modern anticoagulants
Participants were divided based on their use of blood-thinning medication: those taking newer anticoagulants, such as rivaroxaban, those taking warfarin, an older version of the drug, and those not taking any anticoagulants.
Anticoagulants are medications designed to prevent blood clot formation. Warfarin has served as a standard treatment for decades by inhibiting blood clotting factors, but requires regular monitoring due to bleeding risks. Newer direct oral anticoagulants like rivaroxaban target specific clotting factors directly without requiring routine blood tests.
Researchers monitored the brain health of participants using a comprehensive test that assessed patients' memory, language and motor skills.
Results showed that those taking newer anticoagulants experienced a slower decline in cognitive function compared to those receiving warfarin or no anticoagulant treatment.
Experts admit that the difference was slight. Those on newer drugs scored, on average, just under 1 per cent higher on the memory test after a year.
However, the research team argued that over time, this difference would become more significant for patients.
Study co-author Professor Nanbo Zhu said: "While the difference is modest for an individual patient from one year to the next, over a longer period even such an effect could influence how cognitive function develops."
Reduced health risks and bleeding concerns
Patients treated with the newer blood-thinning drugs, which are gradually replacing warfarin, were also found to have a lower risk of premature death, stroke and fractures than those who did not receive anticoagulant treatment.
Warfarin was also associated with a lower risk of death, stroke and blood clots compared to those not on treatment, but was linked to a higher risk of major bleeding.
However, the researchers warned that more studies need to be done before prescribing anticoagulants based on their anticipated benefits.
Welcoming the findings, Dr Richard Oakley, Associate Director of Research and Innovation at Alzheimer's Society, said: "As one in three people will go on to develop dementia in their lifetime it's important we explore every possible avenue to beat it."
Alzheimer's Society is the UK's leading dementia support and research charity, funding scientific studies into diagnosis, care improvement, and preventative therapies.
Atrial fibrillation, where faulty electrical signals affect the rhythm of the heart, is thought to be linked to high blood pressure, according to studies. It is also more common in those aged over 55, men, those with obesity, and smokers.
In turn, the condition is thought to raise the risk of dementia by as much as a third.
Midlife cardiovascular health and dementia prevention
The Swedish study comes after scientists from NYU Langone Health claimed that three health measures in middle age can help ward off dementia for more than a decade.
NYU Langone Health is a major academic medical centre in New York City, recognized for clinical research into cardiovascular and brain health.
Having normal blood pressure, being free from diabetes and not smoking between the ages of 45 and 65 were linked with around 13 additional years of dementia-free life.
Dr Josef Coresh, the study's lead author, said: "Our findings argue that people need to actively avert these factors in midlife as a strategy for preserving brain health for more than a decade."
Dr Coresh added: "Hopefully, these results will encourage people to stop smoking and watch their vascular health closely from age 45 on."
