Blood test could predict dementia 15 years before diagnosis for early drug therapy

Blood test

A blood test to predict dementia up to 15 years earlier could help identify people who could benefit from new Alzheimer’s drugs.

Scientists have identified 11 proteins that will predict dementia in nine out of 10 cases.

Two drugs – donanemab and lecanemab – which slow the disease could soon be available but only about two per cent of eligible patients would receive the medication because diagnosis is so poor.

The new test looks for proteins in the blood which occur when people have dementia and can pick up cases early when drugs will be most beneficial.

Professor Jianfeng Feng, of the University of Warwick’s department of computer science, said: “The test could be seamlessly integrated into the NHS and used as a screening tool by GPs.”

More than 944,000 people in the UK have dementia, with the number expected to rise to more than a million by 2030.

For the study, thought to be the largest of its kind, the researchers looked at data from more than 50,000 healthy people from UK Biobank, which holds medical and lifestyle records of more than half a million Britons.

Treatments must be given early

They analysed the blood samples from this group collected between 2006 and 2010 and found 11 proteins in the 1,400 people who went on to develop dementia.

Dr Sheona Scales, director of research at Alzheimer’s Research UK, said: “New treatments like lecanemab, should they be approved, will only be effective if they are given to people in their early stages of Alzheimer’s and at the moment very few people have access to the specialist tests that would be needed.

“Blood tests could unlock early diagnosis and are showing great promise, but so far, none have been validated for use in the UK.“

The new drugs, which are yet to be approved in Britain, can slow down the disease by around 24 to 30 per cent.

Costs come later down line

However, a BBC Panorama documentary warns that many people will miss out because of poor detection.

Jennifer Kean, head of policy for Alzheimer’s UK, said: “Because we’re not diagnosing it early, a lot of the costs come later on down the line.

“So we’re talking about social care and care for people. If we can shift to a model where we’re diagnosing people early, and we’re intervening early, there’s potential for savings.”

Sir John Hardy, Professor of neurodegenerative disease at University College London, told the programme: “There are only a few centres at the moment who could really give this drug effectively.

“We need to rethink dementia care in the UK. And that’s going to require quite a lot of reorganisation.”

Details of the new blood test were published in the journal Nature Ageing.

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