Biomarkers of neurodegeneration and neural injury as potential predictors for delirium

Abstract Objectives Determine if biomarkers of Alzheimer's disease and neural injury may play a role in the prediction of delirium risk. Methods In a cohort of older adults who underwent elective surgery, delirium case‐no delirium control pairs ( N = 70, or 35 matched pairs) were matched by age, sex and vascular comorbidities. Biomarkers from CSF and plasma samples collected prior to surgery, including amyloid beta (Aβ) 42 , Aβ 40 , total (t)‐Tau, phosphorylated (p)‐Tau 181 , neurofilament‐light (NfL), and glial fibrillary acid protein (GFAP) were measured in cerebrospinal fluid (CSF) and plasma using sandwich enzyme‐linked immunosorbent assays (ELISAs) or ultrasensitive single molecule array (Simoa) immunoassays. Results Plasma GFAP correlated significantly with CSF GFAP and both plasma and CSF GFAP values were nearly two‐fold higher in delirium cases. The median paired difference between delirium case and control without delirium for plasma GFAP was not significant ( p = 0.074) but higher levels were associated with a greater risk for delirium (odds ratio 1.52, 95% confidence interval 0.85, 2.72 per standard deviation increase in plasma GFAP concentration) in this small study. No matched pair differences or associations with delirium were observed for NfL, p‐Tau 181, Aβ 40 and Aβ 42 . Conclusions These preliminary findings suggest that plasma GFAP, a marker of astroglial activation, may be worth further investigation as a predictive risk marker for delirium.