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The Need for Early Diagnosis in A New Era of Alzheimer's Disease

January 9, 2025    Posted by: Eli Lilly and Company

A male sitting on a window sill staring out the window.

Today, an estimated 6.7 million people in the United States are living with Alzheimer’s disease.1 In fact, it's the fifth-leading cause of death among Americans ages 65 and older.2 However, people living with Alzheimer's now have more reasons to be hopeful. Enormous strides have been made in evolving our understanding of the disease, including some of relevant biomarkers, which are measurable indicators of biological processes, disease or response to treatment. There have also been incredible developments in diagnostic tools that can detect these biomarkers and help aid in the diagnosis of Alzheimer's disease as well as new therapies with the potential to slow its progression.

The build-up of two proteins, amyloid and tau, within the brain is characteristic of Alzheimer's disease.3 Amyloid is a protein that can form abnormal clumps of protein fragments, otherwise known as amyloid plaques.4,5 Tau is a protein that can build up twisted fibers, otherwise known as tau tangles, that accumulate inside neurons.6,7 The build-up and spread of these proteins precede the cognitive decline and memory loss associated with Alzheimer’s disease.3

To help slow this decline, there are treatment options available for early symptomatic Alzheimer's disease. This means that in order for patients to be eligible, they must be diagnosed at the earliest signs of symptoms.

The Promise of Blood Testing

Blood tests are a readily accessible tool that can aid in diagnosis of a variety of conditions—from allergies to vitamin deficiencies to cancer, and now even something as complex as Alzheimer’s disease.8

Blood-based biomarker testing, essentially blood testing that specifically looks at key biomarkers to identify a disease pathology,9 can play an important role in the earlier detection of Alzheimer's disease in symptomatic patients. These blood-based biomarker tests can measure tau and amyloid levels, identifying these important biomarkers that can help aid in diagnosing the disease with high accuracy.10,11 In fact, some of these blood-based biomarker tests have demonstrated they can confirm or rule out the presence of amyloid plaques in the brain with a simple blood draw. The results are correlated to the presence of amyloid, in some cases with an accuracy of 90% or above.10,11

Following initial memory and cognitive assessments that help a healthcare professional determine cognitive impairment, blood-based biomarker testing for a patient who meets testing criteria can serve as a less invasive tool to confirm Alzheimer's disease pathology. This testing can also be paired with additional amyloid positron emission tomography (PET) scans or cerebrospinal fluid testing (CSF) to further inform the diagnosis of each patient and allow for more accurate and timely diagnosis.

How To Take Action

These advancements in diagnostics are promising, but it's important that patients or loved ones speak up and take a proactive approach to assessing cognitive decline. At the earliest signs of memory and thinking issues, especially in those 65 or older with a family history of dementia, it's critical. Having these conversations with doctors as early as possible can allow for planning as well as treatment that could help slow the cognitive decline caused by Alzheimer's disease in appropriate patients.

If you or a loved one are experiencing memory or thinking issues, it's important to have a conversation with your doctor about testing. Learn more about the signs and symptoms of Alzheimer’s disease.


References

1 2023 Alzheimer's disease facts and figures. Alzheimers Dement. 2023;19(4):1598-1695. doi:10.1002/alz.13016

2 2024 Alzheimer's disease facts and figures. Alzheimers Dement. 2024;20(5):3708-3821. doi:10.1002/alz.13809

3 What Happens to the Brain in Alzheimer's Disease? National Institute on Aging. Content Reviewed January 19, 2024. https://www.nia.nih.gov/health/alzheimers-causes-and-risk-factors/what-happens-brain-alzheimers-disease

4 Porsteinsson AP, Isaacson RS, Knox S, et al. Diagnosis of early Alzheimer's disease: clinical practice in 2021. J Prev Alzheimers Dis. 2021;3(8):371-386.

5 Alzheimer's Association. 2022 Alzheimer's disease facts and figures. Alzheimers Dement. 2022;18(4):700-789.

6 Aisen PS, Cummings J, Jack CR Jr, et al. On the path to 2025: understanding the Alzheimer's disease continuum. Alzheimers Res Ther. 2017;9(1):60.

7 McDade E, Bednar M, Brashear HR, et al. The pathway to secondary prevention of Alzheimer’s disease. Alzheimers Dement (N Y). 2020;6(1):1-9.

8 Blood Tests. Cleveland Clinic. Content Reviewed December 6, 2022. https://my.clevelandclinic.org/health/diagnostics/24508-blood-tests

9 What are blood tests and blood biomarkers for diagnosing dementia? Alzheimer's Society. https://www.alzheimers.org.uk/research/our-research/dementia-research-news/blood-biomarker-tests

10 Ashton NJ, Brum WS, Di Molfetta G, et al. Diagnostic Accuracy of a Plasma Phosphorylated Tau 217 Immunoassay for Alzheimer Disease Pathology. JAMA Neurol. 2024;81(3):255–263. doi:10.1001/jamaneurol.2023.5319

11 Palmqvist S, Tideman P, Mattsson-Carlgren N, et al. Blood Biomarkers to Detect Alzheimer Disease in Primary Care and Secondary Care. JAMA. 2024;332(15):1245-1257. doi:10.1001/jama.2024.13855