The Association between Skull Bone Fractures and the Mortality Outcomes of Patients with Traumatic Brain Injury

Abstract

Introduction. Skull fractures are often found in patients with traumatic brain injury (TBI). Although skull fractures may indicate greater force impact and are associated with local or diffuse brain injuries, the prognostic value of skull fractures remains unclear. This retrospective study aimed to assess the association between skull fractures and mortality in patients with TBI. Methods. This study included 5,430 TBI patients registered in the trauma registry system from January 2009 to December 2018. Clinical and demographic data including age, sex, trauma mechanisms, comorbidities, Glasgow Coma Scale (GCS) score, abbreviated injury score (AIS)-head, injury severity score (ISS), and in-hospital mortality were acquired. Multiple logistic regression and propensity score matching were used to elucidate the effect of skull fractures on mortality outcomes of TBI patients. Results. Compared to TBI patients without skull fracture, patients with skull fractures were predominantly male, younger, had lower GCS upon arrival at the emergency room, and had higher AIS-head, ISS, and in-hospital mortality. The patients with skull fracture had 1.7-fold adjusted odds of mortality (95% confidence interval (CI): 1.27–2.25; $p<0.001$ ) than those without skull fracture, controlling for age, sex, comorbidities, and AIS-head. Additionally, the propensity score-matched analysis of 1,023 selected paired patients revealed that skull fracture was significantly associated with increased 1.4-fold odds of risk for mortality (95% CI: 1.02–1.88; $p=0.036$ ). Conclusions. Using a propensity score-matched cohort to attenuate the confounding effect of age, comorbidities, and injury severity, skull fracture was identified as a significant independent risk factor for mortality in patients with TBI.