Prognostic significance of cerebrospinal fluid tau biomarkers in amyloid-negative A−T + N + neurodegeneration: A retrospective cohort study

Abstract

Background Amyloid-negative tau-related neurodegeneration represents a non-Alzheimer biomarker-defined profile; however, its clinical heterogeneity and prognostic relevance remain unclear within Alzheimer's disease-related frameworks. Objective To characterize the clinical spectrum and identify predictors of mortality in patients with this profile. Methods In this retrospective cohort study, 1280 patients evaluated at a tertiary neurology center were screened, and 130 with an amyloid-negative cerebrospinal fluid (CSF) pattern [amyloid-β (Aβ)42 normal, phosphorylated tau (pTau), and total tau (tTau) elevated] were included. Survival was assessed using Kaplan–Meier analysis, and predictors of mortality were evaluated using Cox models. Results The cohort (mean age 68.8 ± 10.1 years; 45.4% female) showed heterogeneous diagnoses, mainly mild cognitive impairment and frontotemporal dementia (each 30%). Survival differed across diagnostic groups (log-rank p = 0.037), with more favorable outcomes in mild cognitive impairment. Male sex was more frequent among non-survivors (88.9% versus 45.6%, p < 0.001). Higher CSF tTau levels were associated with mortality in the joint Cox model (HR 1.003, 95% CI 1.001–1.006, p = 0.006) and faster clinical progression (r = 0.22, p = 0.011). When modeled separately, neither tTau nor pTau was independently associated with mortality; however, both became significant in opposite directions when included jointly. Conclusions The amyloid-negative A−T + N + profile represents a clinically heterogeneous subgroup with prognostic relevance. CSF tTau was associated with mortality and faster clinical progression, but the joint-model findings involving tTau and pTau should be interpreted cautiously as hypothesis-generating. Further studies are needed to clarify the prognostic value of tau-related biomarkers in this population.