European consensus for the diagnosis of Alzheimer’s disease is published in The Lancet Neurology by a working group of experts including Alzheimer Europe

15/02/2024

A multidisciplinary working group, consisting of 22 experts from 11 European scientific associations and Alzheimer Europe, has defined recommendations for the effective and individualised use of biomarkers for the diagnosis of Alzheimer’s disease (AD) in memory clinics. Putting patients, instead of the disease or a test, at the centre of doctors’ diagnostic considerations constitutes a turning point in the approaches currently applied. This work has been coordinated by a team from the University Hospital of Geneva (HUG), the University of Geneva (UNIGE) and the Fatebenefratelli of Brescia National Research Center for Alzheimer’s Disease (IRCCS). Their consensus paper has been published in the March 2024 edition of The Lancet Neurology: https://www.sciencedirect.com/science/article/abs/pii/S1474442223004477

The Lancet Neurology has published an editorial for its March 2024 journal, titled "Dementia diagnosis in the anti-amyloid era", which introduces the consensus paper: https://www.thelancet.com/journals/laneur/article/PIIS1474-4422(24)00041-3/fulltext



Individualised diagnostic pathway



Experts from 11 European scientific associations and organisations, as well as Alzheimer Europe, have collaborated to define a diagnostic pathway focused on each individual case which enables the right tests to be identified according to the symptoms profile. The pathway is easy to use in memory clinics and enables a highly reliable diagnosis to be made.

This diagnostic pathway has been developed on the basis of the scientific literature and from the practical experience of the specialists. After having examined the individual's complaints, performed memory tests and conducted a brain MRI, the specialist can now take advantage of these recommendations to classify the case into one of the eleven defined phenotypes, then look for biomarkers using the tests recommended by the international experts, namely lumbar puncture, amyloid PET, glucose PET, ioflupane SPECT, MIBG SPECT and tau PET.



Moving beyond the biomarker-centric approach



The objective of the diagnostic pathway is to overcome the current limitations of the recommendations and guidance related to the diagnosis of AD. The latter focus mainly on the disease itself or on biomarkers, rather than on the person affected. Although they have been developed to help clinicians use the correct diagnostic tests, they reveal gaps when applied in clinical practice. Indeed, most of these recommendations do not take account of the many diagnostic options available nor of the existence of several tests that can be carried out simultaneously or sequentially. Moreover, those that do take these into account often only reflect the opinion of non-representative expert groups. As a result, in clinical practice biomarker choice is often influenced more by organizational and logistical considerations than by clinical factors.

“The diagnostic pathway we have developed will help clinicians define the most informative biomarker in the most frequent clinical case scenarios. It will promote consistency in the diagnosis of neurocognitive disorders in European countries, reduce the cost of analyses and identify those eligible for treatments with more precision,” explains Prof. Giovanni Frisoni, head of the HUG Memory Center, Professor of Clinical Neuroscience at the University of Geneva and first author of the study.



Consensual method



To reach this consensus the 22 experts used the Delphi participatory approach to compare the difference in effectiveness of one test compared to another in various situations. This approach consists of measuring the specialists’ opinion on the characteristics studied in order to retain only those opinions that achieve a consensus of over 70% and therefore considered highly probable.



Next steps



This pooling of expertise has enabled a reference standard to be established that will be useful to all doctors in Europe. It will now be incumbent on national services, healthcare providers, medical officials and insurance companies to implement it in each country.

As far as the study is concerned, the next step will be to integrate blood biomarkers into the decision tree. These are only available currently within the remit of research and are in the process of being approved for clinical use. In future they will avoid up to 70% of invasive tests such as lumbar punctures and PETs, helping to reduce costs and expand diagnoses in the general population.