Risk factors for traumatic intracranial hemorrhage in mild traumatic brain injury patients at the emergency department: a systematic review and meta-analysis.

Background: Mild traumatic brain injury (mTBI), i.e. a TBI with an admission Glasgow Coma Scale (GCS) of 13-15, is a common cause of emergency department visits. Only a small fraction of these patients will develop a traumatic intracranial hemorrhage (tICH) with an even smaller subgroup suffering from severe outcomes. Limitations in existing management guidelines lead to overuse of computed tomography (CT) for emergency department (ED) diagnosis of tICH which may result in patient harm and higher healthcare costs.

Objective: To perform a systematic review and meta-analysis to characterize known and potential novel risk factors that impact the risk of tICH in patients with mTBI to provide a foundation for improving existing ED guidelines.

Methods: The literature was searched using MEDLINE, EMBASE and Web of Science databases. Reference lists of major literature was cross-checked. The outcome variable was tICH on CT. Odds ratios (OR) were pooled for independent risk factors.

Results: After completion of screening, 17 papers were selected for inclusion, with a pooled patient population of 26,040 where 2,054 cases of tICH were verified through CT (7.9%). Signs of a skull base fracture (OR 11.71, 95% CI 5.51-24.86), GCS < 15 (OR 4.69, 95% CI 2.76-7.98), loss of consciousness (OR 2.57, 95% CI 1.83-3.61), post-traumatic amnesia (OR 2.13, 95% CI 1.27-3.57), post-traumatic vomiting (OR 2.04, 95% CI 1.11-3.76), antiplatelet therapy (OR 1.54, 95% CI 1.10-2.15) and male sex (OR 1.28, 95% CI 1.11-1.49) were determined in the data synthesis to be statistically significant predictors of tICH.

Conclusion: Our meta-analysis provides additional context to predictors associated with high and low risk for tICH in mTBI. In contrast to signs of a skull base fracture and reduction in GCS, some elements used in ED guidelines such as anticoagulant use, headache and intoxication were not predictive of tICH. Even though there were multiple sources of heterogeneity across studies, these findings suggest that there is potential for improvement over existing guidelines as well as a the need for better prospective trials with consideration for common data elements in this area. PROSPERO registration number CRD42023392495.