Plasma p-tau217 and tau-PET predict future cognitive decline among cognitively unimpaired individuals: implications for clinical trials

Abstract Plasma p-tau217 and tau positron emission tomography (PET) are strong prognostic biomarkers in Alzheimer’s disease (AD), but their relative performance in predicting future cognitive decline among cognitively unimpaired (CU) individuals is unclear. In a head-to-head comparison study including nine cohorts and 1,474 individuals, we show that plasma p-tau217 and medial temporal lobe tau-PET signal display similar associations with cognitive decline on a global cognitive composite test ( R 2 PET = 0.34 versus R 2 plasma = 0.33, P difference = 0.653) and with progression to mild cognitive impairment (hazard ratio (HR) PET = 1.61 (1.48–1.76) versus HR plasma = 1.57 (1.43–1.72), P difference = 0.322).…