Identifying the severely injured benefitting from a specific level of trauma care in an inclusive network: A multicentre retrospective study.

Introduction: Defining major trauma (MT) with an Injury Severity Score (ISS) > 15 has limitations. This threshold is used for concentrating MT care in networks with multiple levels of trauma care.

Objective: This study aims to identify subgroups of severely injured patients benefiting on in-hospital mortality and non-fatal clinical outcome measures in an optimal level of trauma care.

Methods: A multicentre retrospective cohort study on data of the Dutch National Trauma Registry, region South West, from January 1, 2015 until December 31, 2019 was conducted. Patients ≥ 16 years admitted within 48 h after trauma transported with (H)EMS to a level I trauma centre (TC) or a non-level I trauma facility with a Maximum Abbreviated Injury Scale (MAIS) ≥ 3 were included. Patients with burns or patients of ≥ 65 years with an isolated hip fracture were excluded. Logistic regression models were used for comparing level I with non-level I. Subgroup analysis were done for MT patients (ISS > 15) and non-MT patients (ISS 9-14).

Results: A total of 7,493 records were included. In-hospital mortality of patients admitted to a non-level I trauma facility did not differ significantly from patients admitted to the level I TC (adjusted Odds Ratio (OR): 0.94; 95% confidence interval (CI) 0.68-1.30). This was also applicable for MT patients (OR: 1.06; 95% CI 0.73-1.53) and non-MT patients (OR: 1.30; 95% CI (0.56-3.03). Hospital and ICU LOS were significantly shorter for patients admitted to a non-level I trauma facilities, and patients admitted to a non-level I trauma facility were more likely to be discharged home. Findings were confirmed for MT and non-MT patients, per injured body region.

Conclusion: All levels of trauma care performed equally on in-hospital mortality among severely injured patients (MAIS ≥ 3), although patients admitted to the level I TC were more severely injured. Subgroups of patients by body region or ISS, with a survival benefit or more favorable clinical outcome measures were not identified. Subgroups analysis on clinical outcome measures across different levels of trauma care in an inclusive trauma network is too simplistic if subgroups are based on injuries in specific body region or ISS only.