Prehospital management and hospital outcomes of severely injured patients during routine civilian mass casualty incidents: a 1:4 matched cohort analysis of the TraumaRegister DGU®

Mass casualty incidents (MCIs) pose substantial challenges to prehospital emergency medical systems due to limited resources and the need for rapid prioritization. Evidence regarding the impact of routine civilian MCIs on the management and outcomes of severely injured patients remains limited. This study aimed to evaluate the influence of MCIs on prehospital care, transport strategies, and clinical outcomes compared with routine individual care. Data from the TraumaRegister DGU ® were analysed for patients treated in Germany between mid-2020 and 2023. Patients with severe trauma (Maximum Abbreviated Injury Scale; MAIS ≥ 3) were included. Mass casualty incident cases were identified based on registry documentation. A 1:4 matched cohort was performed using age group, injury pattern and traffic involvement as matching criteria. The primary endpoint was in-hospital mortality; secondary endpoints included prehospital time intervals, performed interventions, and transport strategies. An additional multivariable logistic regression was performed as a sensitivity analysis of the primary endpoint. A total of 65,152 patients were included, of whom 430 were treated during mass casualty incidents (MCIs). After matching, 423 MCI patients were compared with 1,692 controls. Patients treated during MCIs had slightly higher injury severity (Injury Severity Score (ISS) 24.8 vs. 20.3). Median total prehospital time was significantly longer in the MCI group (85 [IQR 67–100] vs. 67 [IQR 53–83] minutes; p < 0.001). Invasive interventions, including prehospital intubation (33.6% vs. 20.9%) and administration of tranexamic acid (32.1% vs. 15.0%) were more frequently performed in the MCI group. Helicopter emergency medical services (HEMS) transport was used more frequently (34.5% vs. 20.7%). In the matched cohort, in-hospital mortality did not differ significantly between groups (13.5% vs. 11.7%; p = 0.317). In an additional multivariable sensitivity analysis, MCI status was not significantly associated with in-hospital mortality (adjusted OR 1.19, 95% CI 0.77–1.85). Mass casualty incidents (MCIs) were associated with prolonged prehospital care and modified transport strategies. No statistically significant difference in in-hospital mortality was observed between MCI patients and matched controls. These findings describe outcomes among severely injured patients captured by the TraumaRegister DGU ® but should be interpreted in light of residual confounding and the observational study design.