Risk of Traumatic Intracranial Hemorrhage After Stroke: A Nationwide Population-Based Cohort Study in Taiwan

BACKGROUND: Stroke and traumatic intracranial hemorrhage (tICH) are major causes of disability worldwide, with stroke exerting significant negative effects on the brain, potentially elevating tICH risk. In this study, we investigated tICH risk in stroke survivors. METHODS AND RESULTS: Using relevant data (2017-2019) from Taiwan's National Health Insurance Research Database, we conducted a population-based retrospective cohort study. Patients were categorized into stroke and nonstroke groups, and tICH risk was compared using a Cox proportional-hazards model. Among 164 628 patients with stroke, 1004 experienced tICH. Patients with stroke had a higher tICH risk than nonstroke counterparts (adjusted hazard ratio [HR], 3.49 [95% CI, 3.17-3.84]). Subgroup analysis by stroke type revealed higher tICH risk in hemorrhagic stroke survivors compared with ischemic stroke survivors (HR, 5.64 [95% CI, 4.97-6.39] versus 2.87 [95% CI, 2.58-3.18], respectively). Older patients (≥45 years) with stroke had a higher tICH risk compared with their younger counterparts (<45 years), in contrast to younger patients without stroke (HR, 7.89 [95% CI, 6.41-9.70] versus 4.44 [95% CI, 2.99-6.59], respectively). Dementia and Parkinson disease emerged as significant tICH risk factors (HR, 1.69 [95% CI, 1.44-2.00] versus 2.17 [95% CI, 1.71-2.75], respectively). In the stroke group, the highest tICH incidence density occurred 3 months after stroke, particularly in patients aged >65 years. CONCLUSIONS: Stroke survivors, particularly those with hemorrhagic stroke and those aged ≥45 years, face elevated tICH risk. Interventions targeting the high-risk period are vital, with fall injuries potentially contributing to tICH incidence.