To identify the association between skull fracture (SF) and in-hospital mortality in patients with severe traumatic brain injury (TBI).

This multicenter cohort study included a retrospective analysis of data from the Japan Trauma Data Bank (JTDB). JTDB is a nationwide, prospective, observational trauma registry with data from 235 hospitals. Adult patients with severe TBI (Glasgow Coma Scale <9, head Abbreviated Injury Scale (AIS) ≥ 3, and any other AIS < 3) who were registered in the JTDB between January 2004 and December 2017 were included in the study. Patients who (a) were < 16 years old, (b) developed cardiac arrest before or at hospital arrival, and (c) had burns and penetrating injuries were excluded from the study. In-hospital mortality was the primary outcome assessed. Multivariable logistic regression analyses were performed to calculate the adjusted odds ratios (ORs) of SF and their 95% confidence intervals (CIs) for in-hospital mortality.

A total of 9607 patients were enrolled [median age: 67 (interquartile range: 50–78) years] in the study. Among those patients, 3574 (37.2%) and 6033 (62.8%) were included in the SF and non-SF groups, respectively. The overall in-hospital mortality rate was 44.1% (4238/9607). A multivariate analysis of the association between SF and in-hospital mortality yielded a crude OR of 1.63 (95% CI: 1.47–1.80). A subgroup analysis of the association of skull vault fractures, skull base fractures, and both fractures together with in-hospital mortality yielded adjusted ORs of 1.60 (95% CI: 1.42–1.98), 1.40 (95% CI: 1.16–1.70), and 2.14 (95% CI: 1.74–2.64), respectively, relative to the non-SF group.

This observational study showed that SF is associated with in-hospital mortality among patients with severe TBI. Furthermore, patients with both skull base and skull vault fractures were associated with higher in-hospital mortality than those with only one of these injuries.