Recent headlines have been dominated by positive news from the CLARITY AD trial of lecanumab, a drug that targets and clears toxic amyloid beta proteins in the brain. Drugs such as lecanumab offer a potential treatment for people with Alzheimer’s disease caused by the accumulation of amyloid plaques, particularly when it is diagnosed early. However, a new study published in JAMA Neurology has found that Black, Hispanic and Asian patients are less likely to have amyloid build-up in their brains, when compared to their White counterparts. People from these ethnic groups are also more frequently diagnosed at the dementia stage rather than the earlier stage of mild cognitive impairment (MCI), when treatments such as lecanumab are likely to be most beneficial. Led by Consuelo Wilkins of Vanderbilt University Medical Center, the study looked at a group of 17,017 Medicare beneficiaries with MCI or dementia, from the Imaging Dementia – Evidence for Amyloid Scanning (IDEAS) cohort. 1785 individuals were Black, Hispanic or Asian, and 15,322 were White.
Participants all underwent a brain PET scan to detect the presence of amyloid plaques in the brain, and researchers compared PET data from participants from different ethnic groups, who were matched 1:1 based on parameters such as age, sex, family history and comorbidities. Statistical analyses revealed that White participants with MCI or dementia were more likely to have positive amyloid-PET scans than participants from other ethnic groups. Asian people were 53% less likely than White people to have amyloid-PET positivity, while Hispanic and Black people were 32% and 29% (respectively) less likely to have amyloid-PET positivity. This may indicate differences in the underlying causes of MCI and dementia between ethnic groups, explained the authors, with factors such as vascular disease, hypertension or diabetes playing a more prominent role than amyloid plaques. The authors also noted that diverse groups may be less likely to benefit from amyloid-directed therapies, and that the clinical rollout of these novel treatment options should be carefully planned to avoid exacerbating existing ethnic disparities in dementia care. Read the full article, here https://jamanetwork.com/journals/jamaneurology/fullarticle/2796653
