Clinical outcomes of conversion to amyloid‐beta positivity in amyloid‐beta negative elderly

Abstract

AbstractBackgroundEarly detection of amyloid beta (Aβ) accumulation has become important as Aβ accumulation begins before clinical symptoms appear. Previous longitudinal studies of Aβ‐negative (Aβ‐) people have shown that some of them convert to amyloid‐positive (Aβ+) and others remain amyloid‐negative. The clinical effects of conversion to Aβ+ have not been extensively investigated, yet. The aim of the study is to investigate the longitudinal cognitive changes according to conversion to Aβ+.MethodWe recruited subjects from 62 Korean subjects from Samsung Medical Center and 275 the Alzheimer’s Disease Neuroimaging Initiative database that were followed for more than three years. All subjects were amyloid PET negative and showed normal cognitive function at baseline. They were followed for more than three years and underwent amyloid PET and clinical dementia rating‐sum of boxes (CDR‐SOB). Longitudinal cognition changes according to conversion to Aβ+ were analyzed using a linear mixed effect model.ResultTwelve (4.4%) of Aβ‐ ADNI participants and three (4.8%) of Aβ‐ Korean participants were converted to Aβ+. The ADNI and Korean subjects showed that CDR‐SOB was significantly deteriorated in the converter group than in the non‐converter group (p = 0.034 for ADNI; p = 0.022 for Korean).ConclusionOur findings revealed that conversion to Aβ+ predicted worse clinical outcomes, suggesting that it is important to recognize potential candidates for primary prevention of AD.