Positive Amyloid PET Scans Vary By Race and Ethnicity in MCI, Dementia

Mild cognitive impairment (MCI) or dementia occurred more frequently among non-Hispanic White adults compared with adults of other racial and ethnic groups based on positive amyloid positron emission tomography (PET) scans. This suggests underlying differences in disease etiology. These are the findings of a study published in JAMA Neurology.

In studies related to Alzheimer disease (AD) biomarkers, including amyloid PET, racial and ethnic groups at a higher risk for clinical AD are underrepresented. For this study, researchers sought to determine whether positive amyloid PET scan rates varied among people in these groups who have MCI or dementia.

The researchers used data from the Dementia-Evidence for Amyloid Scanning (IDEAS) study, a single-arm cohort of Medicare beneficiaries enrolled by dementia specialists at 595 dementia practices for amyloid PET imaging at 343 imaging facilities in the US. For their multicenter cohort study, the researchers obtained amyloid PET scans of 17,107 Medicare beneficiaries (51.3% women) with MCI or dementia between February 2016 and September 2017 following up until January 2018

Classifying these 17,107 individuals according to race/ethnicity, 15,322 were White, 829 Hispanic, 635 Black, and 321 Asian.

After conducting 1:1 matching analysis, White participants exhibited higher numbers of positive amyloid PET scans than Asian participants (57.8%; 95% CI, 52.3-63.2 vs. 45.4%; 95% CI, 39.9-50.9; P =.001) and Hispanic participants (61.8%; 95% CI, 58.3-65.1 vs. 54.5%; 95% CI, 51.0-58.0; P =.003); however, the difference between White and Black participants was not significant (58.4%; 95% CI, 54.4-62.2 vs. 54.1%; 95% CI, 50.2-58.0; P =.13).

White participants also demonstrated a higher risk of positive amyloid PET scans compared with Asian (odds ratio [OR]: 0.47; 95% CI, 0.37-0.59; P <.001), Black (OR: 0.71; 95% CI, 0.60-0.84; P <.001), and Hispanic (OR: 0.68; 95% CI, 0.59-0.79; P <.001) participants.

The researchers found older Asian, Black, and Hispanic adults with MCI and dementia have a lower likelihood of having a positive amyloid PET scan than their non-Hispanic White counterparts.

They concluded that the “Racial and ethnic differences found in amyloid PET positivity among individuals with MCI and dementia in this study may indicate differences in underlying etiology of cognitive impairment and guide future treatment and prevention approaches.”

Study limitations included lack of adequate minority representation in the study, potential selection bias, reliance on appropriate use criteria for study eligibility, lack of a control group, and lack of longitudinal follow-up. Additionally,  the researchers did not assess social and structural determinants of health data or types of control and treatment for hypertension and diabetes which may have impacted progression of cognitive impairments/dementia.

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.