Plasma amyloid-β predicts amyloid-β accumulation in PET A- non-demented participants

Background Plasma biomarkers for Alzheimer's disease (AD) studies, but much remains unknown about the associations of plasma and PET biomarkers of amyloid-β (Aβ). Objective To determine the associations of plasma Aβ with PET Aβ accumulation and progression from PET A- to A + . Methods We evaluated PET A- participants with baseline plasma Aβ measurements and longitudinal indices of PET Aβ. Linear mixed effects models characterized the association of plasma biomarker outcomes with changes in PET Aβ values. Survival analysis evaluated the ability of baseline plasma biomarker A+/- status to differentiate trajectories of progression from PET A- to A + . Results Linear mixed effects models showed significant interactions between time and plasma Aβ 42/40 with respect to longitudinal measures of PET Aβ burden. Survival analysis found that A status determined from plasma Aβ 42/40 predicted distinct patterns of progression from PET A- to A + . Conclusions These models suggest that, in PET A- participants, baseline plasma Aβ 42/40 can be used to predict both how much Aβ will accumulate over time and likelihood of becoming PET A + .