Early Clinical and Cerebrospinal Fluid Predictors of 1‐Year Recurrence in Autoimmune GFAP Astrocytopathy

ABSTRACT Objective Autoimmune glial fibrillary acidic protein astrocytopathy (GFAP‐A) is an inflammatory central nervous system disorder with variable outcomes. Relapse occurs in a subset of patients, but early predictors remain unclear. We aimed to identify admission‐available features associated with 1‐year recurrence and develop an interpretable risk stratification model. Methods We retrospectively included 156 patients with CSF GFAP‐IgG‐positive GFAP‐A between January 2021 and February 2025. Patients were classified by recurrence within 1 year. Early demographic, clinical, CSF, serological, neuroimaging, and treatment‐related variables were compared between groups. Candidate predictors were screened using elastic net regression with repeated cross‐validation, followed by multivariable logistic regression and internal validation. Results Thirty‐five patients (22.4%) relapsed within 1 year. Patients with and without recurrence within 1 year were broadly comparable in age, sex, baseline severity, neuroimaging findings, and treatment exposure. Patients with recurrence within 1 year had lower CSF white blood cell counts (42.0 [10.0–104.0] vs. 107.0 [34.0–200.0] × 10 6 /L; p = 0.002) and more frequent movement disorders (71.4% vs. 43.8%; p = 0.004). The final model included CSF white blood cell count, movement disorders, CSF chloride, and CSF GFAP‐IgG titer category. Lower CSF white blood cell count, movement disorders, and higher GFAP‐IgG titer category were associated with increased recurrence risk. The model showed acceptable optimism‐corrected discrimination (AUC, 0.726), reasonable calibration, and potential clinical utility. Machine‐learning models did not outperform logistic regression. Interpretation In GFAP‐A, 1‐year recurrence was associated with distinct early clinical and CSF features rather than baseline severity or treatment exposure alone. This admission‐based model may support recurrence risk stratification and follow‐up planning.