Predictors of In-Hospital Mortality in Traumatic Acute Subdural Hematoma: The Role of Admission International Normalized Ratio, Imaging Parameters and Neurological Severity

Background/Objectives: Acute subdural hematomas (aSDH) represent a frequent and potentially life-threatening form of traumatic intracranial hemorrhage. This study aims to assess prognostic factors associated with mortality and clinical outcome, with particular emphasis on coagulation-related parameters, especially international normalized ratio (INR). Methods: A single-center retrospective cohort study was performed. We included 151 patients with traumatic aSDH, admitted between January 2020 and June 2025 to the Department of Neurosurgery of the Clinical Emergency Hospital “Saint Pantelimon”. Demographic, clinical, laboratory, and imaging parameters obtained at admission were analyzed. Univariate and multivariable regression analyses were performed to identify predictors of in-hospital mortality. Internal validation included bootstrap resampling, calibration analysis, penalized regression and spline modeling. Results: The cohort had a mean age of 67.4 years and was predominantly male (72.8%). Overall, in-hospital mortality was 36.4%, while 58.3% of patients underwent surgical intervention. Admission Glasgow Coma Scale (GCS) score represented the strongest predictor of mortality. Hematoma thickness was significantly associated with midline shift, mortality, and surgical intervention. Elevated INR was significantly associated with increased hematoma thickness, greater midline shift, lower GCS, and increased mortality. In multivariable analysis, INR ≥ 1.4 remained independently associated with mortality (OR 4.08, 95% CI 1.56–11.29, p = 0.005), together with lower GCS. The final model demonstrated very good discrimination (AUC 0.887) and good calibration. Conclusions: Outcome in traumatic aSDH appears to be influenced by neurological severity, hematoma burden, and coagulation status. Admission GCS remained the strongest predictor of mortality, while elevated INR independently predicted poor outcome.