Trauma Center Level and Mortality in Injured Patients with Shock or Multisystem Trauma

BACKGROUND: Level I and Level II trauma centers share similar clinical verification standards, but differences in volume, subspecialty integration, and transfer patterns may affect outcomes for the highest-risk injured patients. STUDY DESIGN: We performed a retrospective cohort study using the Pennsylvania Trauma Outcomes Study database from 1999-2023. Patients aged ≥16 years treated at established Level I or Level II trauma centers with ISS >9, transfer to a trauma center, or death at a trauma center were included. Patients treated at centers that changed level, Level III/IV centers, burns, age <16 years, ISS <9, and transfers out were excluded from comparative outcome analyses. The primary endpoint was in-hospital mortality. Multivariable logistic regression adjusted for age, GCS, presenting vital signs, mechanism, AIS, ISS, transfer status, and comorbidities. RESULTS: Among 363,470 patients, 247,800 (68.2%) were treated at Level I centers and 115,670 (31.8%) at Level II centers across 11 Level I and 16 Level II facilities. The proportion treated at Level II centers increased from 23.5% in 1999 to 45.2% in 2023. Level I centers treated younger, more severely injured patients and higher proportions transferred in, presenting in shock, or sustaining blunt multisystem or penetrating truncal injury. Overall mortality was 7.7%, with unadjusted mortality of 8.2% at Level I vs 6.9% at Level II centers. After adjustment, mortality did not differ overall. However, Level I centers had lower adjusted mortality among patients with blunt multisystem trauma and those presenting in shock; no adjusted mortality difference was observed for penetrating truncal injury, isolated traumatic brain injury, or ISS strata. CONCLUSIONS: In this mature statewide trauma system, Level I and Level II centers had similar adjusted overall mortality, but Level I centers demonstrated a survival advantage for shock and blunt multisystem trauma. These findings support targeted triage and early-transfer strategies for physiologically unstable and complex blunt-injury patients.EQUATOR Guidelines - STROBE guidelines. LEVEL OF EVIDENCE: Level III.