Predictors of 7-Day In-Hospital Mortality in Older Adults with Traumatic Brain Injury: A Retrospective Cohort Study

Abstract This article aims to quantify 7-day in-hospital mortality in older adults (≥ 65 years) admitted with traumatic brain injury (TBI) and to determine early, pathway-specific predictors in surgically and conservatively managed patients. Because surgical and conservative management represent distinct clinical decision pathways with differing physiologic risks, predictors were evaluated separately for each pathway. Among survivors beyond day 7, short-term in-hospital outcomes were compared. We conducted a retrospective cohort study of adults aged ≥65 years admitted with TBI from January 2021 to December 2024 at a tertiary neurosurgical center. Management pathways were defined by whether cranial neurosurgery occurred during the index admission. The primary outcome was 7-day in-hospital mortality; secondary outcomes included complications and ICU and hospital length of stay (LOS) among 7-day survivors. Univariable logistic regression was performed separately for surgical and conservative pathways. Prespecified multivariable models were estimated using Firth's bias-reduced logistic regression to account for small-event bias. Effect sizes are reported as adjusted odds ratios (aORs) with 95% confidence intervals (CIs) and p-values. Among 545 patients (surgical, N = 164; conservative, N = 381), 7-day in-hospital mortality was 9.5% overall (7.3% surgical; 10.5% conservative). In the surgical pathway, admission GCS score ≤ 8 (aOR: 32.94; 95% CI: 5.50–197.23; p < 0.001) and massive transfusion ≥10 packed red blood cell units (aOR: 24.13; 95% CI: 1.83–318.29; p = 0.016) independently predicted early mortality. In the conservative pathway, admission GCS score ≤ 8 (aOR: 12.92; 95% CI: 5.56–30.03; p < 0.001), nonreactive pupil(s) (aOR: 7.82; 95% CI: 2.66–22.94; p < 0.001), and hypoalbuminemia (<3.5 g/dL) (aOR: 3.63; 95% CI: 1.55–8.48; p = 0.003) were independently predictive. Among patients surviving beyond day 7, surgically managed patients had longer ICU LOS (median: 6 vs. 1 days; p < 0.001), longer hospital LOS (median: 10 vs. 6 days; p < 0.001), and higher rates of pulmonary complications and ventilator support (p < 0.01 for both). Early neurologic severity was the dominant predictor of 7-day mortality across pathways. Survivors managed surgically experienced greater early morbidity and longer ICU/hospital stays, underscoring the need for accurate early risk stratification and pathway-specific perioperative and neurocritical care.