Prognostic value of CAR, FIB-4, and procalcitonin in subdural hematoma: associations with mortality and 90-day functional outcomes running title: CAR, FIB-4, and procalcitonin in SDH outcomes

Aims: This study aimed to investigate the prognostic value of C-reactive protein/albumin ratio (CAR), Fibrosis-4 (FIB-4) Index, procalcitonin, and hemoglobin, in conjunction with clinical severity scores, for predicting 28-day mortality and 90-day functional outcomes in patients with SDH. Methods: We conducted a retrospective cohort study including 118 adult SDH patients admitted to the intensive care unit of a tertiary university hospital between February 2021 and January 2025. Laboratory parameters (CRP, albumin, procalcitonin, CAR, FIB-4, NLR, PLR, and others) and clinical severity scores (GCS, APACHE II, SOFA) were recorded within the first 24 hours of admission. Primary outcomes were 28-day mortality and 90-day functional status assessed with the modified rankin scale (mRS), dichotomized as favorable (0-2) or poor (≥3). Results: The 28-day mortality rate was 19.5%, and poor 90-day functional outcome was observed in 54.2% of patients. Advanced age, elevated CAR, FIB-4, and procalcitonin levels, along with low albumin and hemoglobin levels, were significantly associated with poor outcomes (all p