Black and Latinx Medicare beneficiaries with cognitive impairment showed significantly lower odds of amyloid PET positivity than patients from all other races, according to a study published May 27 in Alzheimer's and Dementia.
The findings highlight the need to develop diagnostic tools and treatments for dementias to ensure equitable care is available to all people, given that Black and Latinx older adults face 1.5 to two times the risk of clinical Alzheimer's disease and related dementias compared with white adults, the researchers noted.
“These results suggest that the yawning ethnoracial differences in dementia may be driven in part by group differences in underlying causes of dementia symptoms,” said corresponding author Consuelo Wilkins, MD, of Vanderbilt University in Nashville, TN, in a news release.
Amyloid plaque deposits in the brain are one of the hallmarks of Alzheimer’s disease, with amyloid PET scans among the most effective diagnostic tools for identifying the pathology. Moreover, positive amyloid PET scans are required for patients to be eligible for recently approved new treatments, the researchers explained. While previous studies have found ethnoracial differences in amyloid PET positivity, they have been limited by a lack of inclusion of minoritized individuals, they noted.
To better contextualize racial and ethnic differences, as well as to identify any social determinants of health (SDOH) that may be driving differences, Wilkins and colleagues analyzed data from 5,757 Medicare beneficiaries with mild cognitive impairment or dementia. Subjects had participated in the New IDEAS study, which included 1,248 Black participants (21.7%), 1,166 Latinx participants (20.3%), and 3,343 participants of all other races/ethnicities (AORE) (58.1%). Amyloid PET scans were performed at accredited imaging centers using one of three FDA-approved radiotracers, with results classified as positive or negative.
According to the results, AORE participants had the highest rate of amyloid PET positivity at 60.0%, compared with 50.1% for Black participants and 45.6% for Latinx participants. Further analysis revealed that compared to AORE, odds of amyloid positivity were 28% lower among Black people and 22% lower among Hispanic people.
In addition, neither gender, type of Medicare plan, nor educational attainment showed statistically significant association with amyloid PET positivity. Meanwhile, neighborhood-level deprivation as measured by the Area Deprivation Index showed an independent association. Participants in the most distressed category had 1.4 times the odds of a positive result compared with those in the prosperous group. Finally, Black and Hispanic participants were more likely to present at the dementia stage rather than with mild cognitive impairment, the researchers reported.
“We need desperately to combat the scourge of Alzheimer’s, but our results highlight that a fixation on Alzheimer’s pathology, to the exclusion of other causes of dementia, could inadvertently worsen stark ethnoracial health differences,” Wilkins said.
Ultimately, the cause of differing amyloid PET positivity rates across ethnoracial groups is still not well understood, the group wrote.
"Future work should include more comprehensive assessment of SDOH as well as examination of medical comorbidities and non-AD neuropathologies to identify potential causes for these observed differences," the researchers concluded.
The full study is available here.
