I want to get tested.” He’s referring to the new Alzheimer’s blood-based biomarkers.
advertisement Enter the blood-based biomarkers, which can detect the amyloid plaques and tau tangles that define Alzheimer’s through a simple blood test.
The above scenario is illustrative of the complex challenges that blood-based biomarkers present to the health care system.
In turn, the widespread adoption of these tests could strain health care resources, potentially diverting attention from other critical areas.
Only through a careful and methodical approach to their integration into the health care ecosystem will the full potential of these technologies be realized.
The patient says during a yearly physical: “Doctor, I saw an advertisement about a blood test that can determine whether I’ll get Alzheimer’s. I saw my mom go through it. I’d like to be tested. “.”.
He’s talking about the new blood-based biomarkers for Alzheimer’s. He is obviously concerned even though he does not exhibit any signs of Alzheimer’s disease; he drives, shops, handles his own finances, and prepares elaborate meals for his wife.
“All right, I can order the test, but there may be some out-of-pocket expenses,” the doctor responds. He appears relieved. She tells him, “But just so you know, we’re still not sure what to do with a positive result.”. “.”.
The discovery of anti-amyloid antibodies for the treatment of Alzheimer’s disease has ushered in a new era of dementia care. These treatments are the first AD medications approved by the FDA to be made available in almost two decades. These disease-modifying therapies have made it crucial to detect Alzheimer’s disease accurately and efficiently, particularly since early detection enables more effective treatment. The development of blood-based biomarkers has created new clinical and ethical difficulties for the diagnosis and treatment of Alzheimer’s disease by potentially detecting the condition before symptoms appear.
Alzheimer’s is currently diagnosed through a challenging process that frequently involves neuropsychological batteries, MRIs, PET scans, and CSF testing, all of which are expensive and only available at specific specialty clinics.
Then come blood-based biomarkers, which can identify Alzheimer’s disease by a straightforward blood test by looking for the tau tangles and amyloid plaques that characterize the disease. Together with conventional testing, these innovative assays have a high diagnostic accuracy of 85–90%, making them capable of accurately diagnosing Alzheimer’s disease in patients exhibiting cognitive decline. The significance of these two breakthroughs for Alzheimer’s diagnosis and treatment cannot be emphasized. Although its complete effectiveness is still unknown, lecanemab’s approval in July 2023 has given us the capacity to identify and treat the underlying pathological process of Alzheimer’s disease.
Going back to our patient. Imagine that his blood test shows that he has tau tangles and amyloid plaques. What comes next? He is fully functional for his age and shows no signs of Alzheimer’s. You make the decision to send him to a neurologist for additional assessment. An MRI they get reveals a healthy brain. Testing for neuropsychology is typical. Our dilemma now is whether to formally diagnose him with Alzheimer’s disease even though he doesn’t exhibit any symptoms, and if so, whether to start anti-amyloid medication therapy. The answers to these questions will determine billions of dollars and the lives of millions of people.
The scenario described above serves as an example of the intricate difficulties that the healthcare system faces when dealing with blood-based biomarkers. On the plus side, early detection enables people to modify their lifestyles to slow the progression of Alzheimer’s. Reduced brain amyloid burden has been linked to a healthier diet, more exercise, and vigorous treatment of long-term illnesses like diabetes and hypertension. Blood-based biomarker testing can give vital information to people with a family history of Alzheimer’s, allowing preventative measures to be taken before symptoms appear. Finally, anti-amyloid medications may be able to slow the progression of the disease if given early, even though they are not yet approved for asymptomatic patients.
That promise, though, has yet to come to pass. There is ongoing discussion regarding the clinical usefulness of these tests in asymptomatic people, especially since amyloid buildup does not always indicate the onset of Alzheimer’s. In the meantime, if there is no obvious way forward, a positive outcome could cause serious distress.
Using blood-based biomarkers widely has significant financial ramifications. Patients bear a significant financial burden as a result of the high cost of these tests and any follow-up treatments, which may not be fully covered by insurance. Who should get tested, and who will pay for it? Universal testing may help some people receive better results and earlier interventions, but it also raises the possibility of overdiagnosis and overtreatment. These ethical concerns center on equity and access. Consequently, if these tests are widely used, they may put a burden on healthcare resources and take focus away from other important areas.
Therefore, it is imperative that we establish stringent guidelines for who should be tested and when. In order to ascertain whether anti-amyloid treatments administered to asymptomatic individuals prevent cognitive decline and whether asymptomatic individuals with positive blood tests eventually develop clinical Alzheimer’s, a research infrastructure must be established. An unbiased agency, like the U.S. S. . The Preventive Services Taskforce will create guidelines for the screening of asymptomatic individuals using blood-based biomarkers. Primary care physicians, geriatricians, and neurologists must be prepared to inform their patients about the possible advantages and drawbacks of these treatments.
We must be cautious to weigh the potential of these tools against their risks and associated expenses as we embark on this new era of Alzheimer’s diagnosis and treatment. To guarantee that blood-based biomarkers are supplied in an economical and equitable manner, manufacturers, trade associations, patient advocacy organizations, and governmental bodies will need to work closely together in the real world. These technologies will only reach their full potential if their integration into the health care ecosystem is done carefully and methodically.
Neurology professor Naveen Reddy is a health policy fellow at the University of California, San Francisco. Kristine Yaffe is the director of UCSF’s Center for Population Brain Health and the vice chair of the university’s departments of psychiatry, neurology, and epidemiology.
