Incidence, demographics and outcomes of patients with penetrating injury: a Japanese nationwide 10-year retrospective study.

Background: Unintentional injury remains the leading cause of death among Japanese people younger than 35 years; however, data are limited on the evaluation of characteristics, long-term mortality trend and mortality risk of patients with penetrating injury in Japan. This prevents the development of effective strategies for trauma care in patients with penetrating injury.

Methods: This retrospective cohort study investigated 313 643 patients registered in the Japan Trauma Data Bank (JTDB) dataset between 1 January 2009 and 31 March 2018. The inclusion criteria comprised patients with penetrating injuries transferred from the injury site by emergency vehicles. Moreover, the patients registered in the JTDB dataset were included in this study regardless of age and sex. Outcomes measured were nationwide trends of characteristics, in-hospital mortality and in-hospital mortality risk among Japanese patients with penetrating injury. The mortality risk was analysed by hospital admission year, age, Injury Severity Score (ISS) and emergency procedures.

Results: Overall, 7132 patients were included. Median age significantly increased during the 10-year study periods (from 48 to 54 years, p=0.002). Trends for the mechanism of injury did not change; the leading cause of penetrating injury was stab wounds (SW: 76%-82%). Overall, the in-hospital mortality rate significantly decreased (4.0% to 1.7%, p=0.008). However, no significant improvement was observed in the in-hospital mortality trend in all ISS groups with SW and active bleeding. Patients with active bleeding who underwent urgent transcatheter arterial embolization had significantly lower mortality risk (p=0.043, OR=0.12, 95% CI=0.017 to 0.936). Conversely, the surgical procedure for haemostasis did not improve the mortality risk of patients with SW and active bleeding.

Conclusion: The severity-adjusted mortality trend in patients with penetrating injuries did not improve. Moreover, patients with active bleeding who underwent urgent surgical procedure for haemostasis had a higher mortality risk.