Challenges in Saving Trauma Patients in Seoul Based on the 2016–2020 Community-Based Severe Trauma Survey

<b>Background/Objectives</b>: The preventable trauma death rate (PTDR) reflects the quality of trauma management systems. In the Republic of Korea, the PTDR in Seoul, the capital city, decreased from 30.8% in 2015 to 20.4% in 2019. However, it remains the highest in the country. In contrast, Gyeonggi-Incheon, which includes Gyeonggi Province and Incheon Metropolitan City surrounding Seoul, had the lowest nationwide PTDR (27.4% in 2015 to 13.1% in 2019). This study aimed to investigate the characteristics and in-hospital mortality risk factors for patients with trauma in Seoul and Gyeonggi-Incheon. <b>Methods</b>: This retrospective cohort study used data from a 2016 to 2020 Community-Based Severe Trauma Survey. Among 237,616 patients, 24,448 were included in the study after applying the inclusion and exclusion criteria. <b>Results</b>: The proportions of the population with motor vehicle and workers' compensation insurance increased with increasing injury severity in both regions. The injury severity score (ISS) was significantly higher in Gyeonggi-Incheon in the ISS < 9 and ISS 9-15 groups. Across all hospital levels, the proportion of patients who visited regional trauma centers in Seoul was low across all three ISS groups (0.2%[<i>n</i> = 26], 0.6%[<i>n</i> = 23], and 1.9%[<i>n</i> = 56] for ISS < 9, ISS 9-15, and ISS > 15, respectively). Conversely, in Gyeonggi-Incheon, the proportion of patients who visited regional trauma centers increased as injury severity increased across all three ISS groups (37.3%[<i>n</i> = 1404], 50.6%[<i>n</i> = 732], and 64.4%[<i>n</i> = 856] for ISS < 9, ISS 9-15, and ISS > 15, respectively). In Seoul, the identified in-hospital mortality risk factors included age, National Health Insurance (NHI) loss, other insurance, ISS, regional and local emergency centers or institutes, and the number of angioembolizations. In Gyeonggi-Incheon, the in-hospital mortality risk factors included age, ISS, falls and slippage, and the number of angioembolizations. <b>Conclusions</b>: The unique in-hospital mortality risk factors in Seoul compared with those in Gyeonggi-Incheon include transfers to regional emergency centers (ISS > 15), local emergency centers or institutes (ISS > 15), NHI loss (ISS 9-15 and ISS > 15), and the use of other insurance (ISS > 15).