Blood-thinning tablets may help slow the progression of Alzheimer’s disease by boosting blood flow to the brain, according to new research.
The medicines are routinely prescribed to more than 1.6 million people in the UK with atrial fibrillation, a common heart rhythm disorder that raises the risk of blood clots and stroke.
Atrial fibrillation is far more common in older adults, including people who are at increased risk of dementia or already living with the memory-robbing condition.
Researchers in Sweden now say blood-thinning drugs could play a role in slowing cognitive decline in Alzheimer’s patients by helping improve circulation in the brain.
But the scientists did not go as far as advising the treatment for people who do not have atrial fibrillation. The apparent benefits were also limited to patients taking newer forms of blood thinners.
Specialists say the findings could matter for the estimated one million people in the UK currently living with dementia, of which Alzheimer’s disease is the most common form. That number is projected to climb to 1.4 million by 2040.
Writing in the European Heart Journal, the study’s 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 study, led by experts at Karolinska University Hospital, examined data from 7,308 people with both atrial fibrillation and Alzheimer’s disease, using information from the Swedish Register for Cognitive Disorders.
Newer anticoagulants could help slow down Alzheimer’s progression by improving blood flow to the brain
Participants were divided based on their use of blood-thinning medication: those on newer anticoagulants (such as rivaroxaban), those taking warfarin – an older version of the drug – and those not taking any anticoagulants.
The researchers monitored their brain health using a 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, on average, scored just under 1 per cent higher on the memory test after a year.
But they argue that, over time, this difference would become more significant.
‘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,’ Professor Nanbo Zhu, the study’s co-author, said.
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 with a higher risk of major bleeding.
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However, more studies need to be done before prescribing anticoagulants based on their anticipated benefits, the researchers warned.
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.’
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.
The new 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.
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.
‘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 Josef Coresh, the study’s lead author, said.
‘Hopefully, these results will encourage people to stop smoking and watch their vascular health closely from age 45 on.’
