Plasma phosphorylated tau (p-tau231) and total tau (t-tau) as prognostic markers of neurological outcome after cardiac arrest - a multicentre study.

Purpose: We studied the promising Alzheimer biomarker plasma tau phosphorylated at threonine 231 (p-tau231) in a cohort of cardiac arrest patients who survived to intensive care to predict long-term neurological outcomes. We also compared it to total tau (t-tau), which has demonstrated predictive abilities of neurological outcome post-cardiac arrest.

Methods: This observational multicentre cohort study included 425 patients admitted to intensive care after cardiac arrest. Plasma p-tau231 was retrospectively analysed at admission, 12 and 48 h after cardiac arrest. The association of the Cerebral Performance Category (CPC) with p-tau231 was analysed with a one-way analysis of variance (ANOVA). CPC was modelled using multivariate ordinal logistic regression, and the biomarkers' prognostic performance was assessed by the area under the receiver operating characteristic curve (AUC).

Results: Increasing p-tau231 levels were significantly associated with worse CPC (p < 0.001). P-tau231 showed moderate prognostic abilities (AUC: 0.69 on admission, 0.72 at 12 h, and 0.71 at 48 h) for all patients but did not improve neurological prognostication after adjusting for clinical covariates. Elevated levels of t-tau were significantly associated with a worse outcome at all time points (p < 0.001). T-tau significantly improved neurological prognosis at 48 h after adjusting for covariates (AUC: 0.95, 95 % CI 0.93-0.98, p < 0.001) compared to the clinical covariate reference model (AUC: 0.88, 95 % CI 0.84-0.93).

Conclusions: Although p-tau231 showed moderate neurological prognostic ability, t-tau was a stronger predictor, particularly at 48 h, even after adjusting for clinical covariates.