Age-Related Comparative Study of In-Hospital Mortality, Functional Outcome, and Recurrence in a Large Cohort of Patients Surgically Treated for Chronic Subdural Hematoma

<b>Background/Objectives:</b> Chronic subdural hematoma (CSDH) predominantly affects the elderly population. To optimize care and quality in this demographic, tailored, age-specific counseling and therapeutic decision-making are imperative. Accordingly, this study aimed to identify risk factors for in-hospital mortality and functional outcome at discharge following surgery using an age-stratified approach. <b>Methods:</b> We conducted a retrospective analysis of symptomatic CSDH patients who underwent surgery at our institution between June 2012 and December 2023. Subjects were categorized into three age cohorts: younger adults (18-64 years), older adults (65-79 years), and the oldest old (≥80 years). Clinical and neurological statuses at admission and discharge were evaluated using the Glasgow Coma Scale (GCS) and modified Rankin Scale (mRS), with mRS scores > 3 indicating poor functional outcomes. <b>Results:</b> Among 879 CSDH patients (mean age 75 ± 11.9 years), the sex ratio shifted progressively from a male predominance in younger adults (1:3.2) to a more balanced ratio in the oldest old (1:1.7). In the multivariate analysis, poor admission mRS and GCS score ≤ 7 predicted in-hospital mortality for older adults, while atrial fibrillation and postoperative pneumonia were significant in the oldest old. Poor admission mRS and multimorbidity consistently forecast unfavorable outcomes alongside other predictors, such as preoperative altered state of consciousness, epilepsy, dementia, unilateral CSDH, postoperative seizure, bleeding, and pneumonia varying by age cohort. Recurrence-free intervals were significantly extended with increasing age. <b>Conclusions:</b> This large-scale, age-stratified analysis delineates critical predictors of in-hospital mortality and unfavorable functional outcomes in surgically treated CSDH patients. These findings offer valuable guidance for neurosurgeons in preoperative risk assessment and inform age-specific counseling strategies to better communicate prognosis and tailor treatment plans.