Metabolic and renal factors associated with plasma phosphorylated tau analytes used to detect Alzheimer's disease pathology

Introduction: We examined the extent to which insulin resistance (IR), type 2 diabetes mellitus, obesity, and kidney function are associated with plasma phosphorylated tau (p-tau) concentrations (p-tau181, p-tau217, p-tau231) in the same cohort and the contribution of these factors on amyloid positron emission tomography (PET) concordance and longitudinal p-tau levels. Methods: , receiver operating characteristic analysis, and linear mixed models. Results: Concordance between plasma p-tau217 and amyloid PET was not influenced by IR or estimated glomerular filtration rate (eGFR). Accounting for eGFR improved concordance of p-tau181 and p-tau231 with amyloid PET. Age, binarized waist-to-hip ratio, and amyloid status were associated with all longitudinal p-tau concentrations, and eGFR associated with longitudinal p-tau231. Discussion: Metabolic factors may influence the interpretation of longitudinal plasma p-tau concentrations and kidney function may influence amyloid PET concordance for p-tau181 and p-tau231, potentially necessitating analyte-specific adjustments or considerations in clinical interpretation.