The impact of infection complications after trauma differs according to trauma severity.

The impact of infection on the prognosis of trauma patients according to severity remains unclear. We assessed the impact of infection complications on in-hospital mortality among patients with trauma according to severity. This retrospective cohort study used a nationwide registry of trauma patients. Patients aged ≥ 18 years with blunt or penetrating trauma who were admitted to intensive care units or general wards between 2004 and 2017 were included. We compared the baseline characteristics and outcomes between patients with and without infection and conducted a multivariable logistic regression analysis to investigate the impact of infection on in-hospital mortality according to trauma severity, which was classified as mild [Injury Severity Score (ISS) < 15], moderate (ISS 15-29), or severe (ISS ≥ 30). Among the 150,948 patients in this study, 10,338 (6.8%) developed infections. Patients with infection had greater in-hospital mortality than patients without infection [1085 (10.5%) vs. 2898 (2.1%), p < 0.01]. After adjusting for clinical characteristics, in-hospital mortality differed between trauma patients with and without infection according to trauma severity [17.1% (95% CI 15.2-18.9%) vs. 2.9% (95% CI 2.7-3.1%), p < 0.01, in patients with mild trauma; 14.8% (95% CI 13.3-16.3%) vs. 8.4% (95% CI 7.9-8.8%), p < 0.01, in patients with moderate trauma; and 13.5% (95% CI 11.2-15.7%) vs. 13.7% (95% CI 12.4-14.9%), p = 0.86, in patients with severe trauma]. In conclusion, the effect of infection complications in patients with trauma on in-hospital mortality differs by trauma severity.