Plasma p‐tau217 concordance with amyloid PET among ethnically diverse older adults

Abstract

Abstract INTRODUCTION Commercially available plasma p‐tau217 biomarker tests are not well studied in ethnically diverse samples. METHODS We evaluated associations between ALZPath plasma p‐tau217 and amyloid‐beta positron emission tomography (Aβ‐PET) in Hispanic/Latino (88% of Cuban or South American ancestry) and non‐Hispanic/Latino older adults. One‐ and two‐cutoff ranges were derived and evaluated to assess agreement with Aβ‐PET. RESULTS A total of 239 participants underwent blood draw and Aβ‐PET (age 70.8 ± 7.8, 55.2% female, education 15.6 ± 3.4 years, 48.9% Hispanic/Latino, 94.9% white). Plasma p‐tau217 showed excellent discrimination of Aβ‐PET positive and negative participants (visual read: AUC = 0.91 [0.87–0.95], p < 0.001; Centiloids quantification: AUC = 0.90 [0.86–0.94]). There was a greater percent agreement between low p‐tau217 and negative Aβ‐PET (95.8%) than high p‐tau217 and positive Aβ‐PET (86.3%). Analyses within ethnicity‐specific subgroups suggested similar p‐tau217 performance. DISCUSSION Plasma p‐tau217 (ALZPath) relates to brain Aβ in Hispanic/Latino and non‐Hispanic/Latino older adults. Independent validation and replication are necessary to establish reference ranges and inform appropriate contexts of use across ethno‐racially diverse populations. HIGHLIGHTS Plasma p‐tau217 (ALZPath) and Aβ‐PET were measured in Hispanic/Latino and non‐Hispanic/Latino older adults. Plasma p‐tau217 accurately discriminated Aβ‐PET positive and negative participants. Applying a two‐cutoff “intermediate” plasma p‐tau217 approach could reduce need for more invasive and costly testing. Plasma p‐tau217 associations with Aβ‐PET were strong within both Hispanic/Latino and non‐Hispanic/Latino groups.

Keywords

• Alzheimer's
• ALZPath
• amyloid PET
• biomarkers
• dementia
• ethnicity