Could biomarker-driven Alzheimer’s care widen existing disparities? Lessons from the New IDEAS study

Large real-world study highlights important ethnoracial differences in amyloid positivity and their implications for diagnosis, treatment and clinical trial access

As amyloid biomarkers become central to Alzheimer’s disease diagnosis and treatment, a new analysis from the New IDEAS (Imaging Dementia—Evidence for Amyloid Scanning) study raises an important question for clinicians: Are current diagnostic pathways equally applicable across all patient populations?

Published in Alzheimer’s & Dementia, the study analysed amyloid PET imaging from 5,757 cognitively impaired Medicare beneficiaries across the United States, representing one of the largest and most ethnically diverse cohorts studied to date.¹

To explore the clinical implications of these findings, touchNEUROLOGY spoke with Dr Christopher Weber, PhD, Senior Director of Global Scientific Initiatives at the Alzheimer’s Association, who discusses what the results may mean for equitable diagnosis and treatment of Alzheimer’s disease.

Unlike previous studies that predominantly included White participants, approximately 22% of participants identified as Black and 20% as Latino/Hispanic, providing a more representative assessment of real-world clinical practice.

Looking beyond amyloid

The lower prevalence of amyloid positivity does not suggest that Black and Latino/Hispanic patients are less likely to experience dementia. Instead, it may indicate that different pathological processes contribute more frequently to cognitive impairment in these populations.

Dr Christopher Weber said the findings point towards a potentially greater contribution of vascular and mixed dementias.

“These results suggest there may be a higher burden of vascular or mixed dementias in Black and Latino/Hispanic populations, which are closely linked to hypertension, diabetes and other dementia risk factors that are more common in these groups.” – Dr Christopher Weber

The study authors similarly note that vascular risk factors are more prevalent in these populations and may contribute to non-Alzheimer causes of cognitive impairment, highlighting the need to consider alternative pathological mechanisms when evaluating patients with dementia.

For clinicians, the findings reinforce that a negative amyloid biomarker should not be interpreted as the absence of significant neurodegenerative disease, but rather prompt consideration of alternative or mixed underlying pathologies.

A changing treatment landscape

The arrival of disease-modifying anti-amyloid therapies has fundamentally changed Alzheimer’s care. However, access to these treatments depends on demonstrating amyloid pathology.

Dr Christopher Weber believes this creates a new challenge:

“The Alzheimer’s field is in the midst of a major shift in earlier detection and treatment thanks to new diagnostic biomarkers and anti-amyloid therapies. However, these advances depend heavily on the presence of amyloid detected by biomarker or imaging tests, which are usually required for treatment eligibility, specialist referral and clinical trial participation.” 

Consequently, patients who are less likely to demonstrate amyloid pathology may also be less likely to qualify for these therapies, despite experiencing significant cognitive impairment.

The study authors conclude that current treatment pathways risk disproportionately excluding some patient populations from both approved therapies and future clinical trials if alternative causes of dementia are not equally prioritised.

Beyond biology: Structural barriers remain

The study also identified disparities extending beyond biomarker status.

Black participants were 2.7 times more likely, and Latino/Hispanic participants 2.5 times more likely, to be enrolled in Medicare Advantage plans than participants from other racial and ethnic groups.

Previous research has shown that patients enrolled in these plans may encounter greater challenges obtaining approval for amyloid PET imaging, creating additional barriers before treatment eligibility can even be assessed.

Dr Christopher Weber notes that these structural issues are equally important:

“Researchers found significant ethnoracial differences in amyloid positivity, with important implications for equity in diagnosis, treatment and future drug development.”

Taken together, the biological differences identified by the study and existing healthcare access barriers could compound disparities as biomarker-guided care becomes increasingly routine.

What should clinicians take away?

Although amyloid biomarkers are transforming Alzheimer’s disease diagnosis, the findings highlight the importance of maintaining a broad diagnostic perspective.

For patients with cognitive impairment but negative amyloid biomarkers, clinicians should continue evaluating for vascular cognitive impairment, mixed dementias and other neurodegenerative conditions rather than viewing negative amyloid status as the end of the diagnostic pathway.

Equally important is recognising that populations already experiencing disparities in dementia diagnosis may face additional barriers to accessing emerging therapies if biomarker-driven pathways are implemented without consideration of broader disease mechanisms.

Future directions

The New IDEAS investigators emphasise that further work is needed to understand why amyloid positivity differs across populations and how dementia care can evolve to better serve all patients.

For Dr Christopher Weber, the message is clear:

“As anti-amyloid treatments and biomarkers reshape Alzheimer’s medicine, this study cautions that large segments of the population may still be left behind, potentially widening existing disparities. We need to pay more attention to non-Alzheimer’s causes of cognitive impairment and develop strategies that improve equity in diagnostics, clinical trials and treatment.”

As precision medicine continues to redefine Alzheimer’s disease management, ensuring that advances benefit diverse patient populations will remain an important challenge for clinicians, researchers and healthcare systems alike.

References:

1. Bolton CJ, Dilworth-Anderson P, Steingrimsson J, Thangarajah M, Hanna L, Gatsonis C, et al. Differences in amyloid PET positivity based on ethnoracial group and social determinants of health: The New IDEAS study. Alzheimers Dement. 2026;22(5):e71406. doi:10.1002/alz.71406.