The Relation Between Trauma Center Outcome and Volume in the National Trauma Databank

BACKGROUND: Regionalization of trauma care services aims to improve outcomes by limiting trauma care delivery to a select group of dedicated trauma centers. However, the evidence linking trauma center volume and outcome is not conclusive. The objective of this study was to examine the volume-mortality relation for patients with severe trauma in the National Trauma Databank. METHODS: This study was based on data for adult patients 18 years of age or older in the National Trauma Databank with an Injury Severity Score (ISS) of 15 or more who sustained either blunt or penetrating trauma. The main outcome measure was in-hospital survival as a function of trauma center volume. Logistic regression modeling was used to analyze the relation between survival and hospital volume for patients sustaining either severe blunt or severe penetrating trauma. RESULTS: For the blunt trauma cohort, model diagnostics showed that the single highest-volume center was an outlier. After exclusion of the patients from this center, no association could be demonstrated between trauma volume and outcome (p = 0.465) for blunt trauma. A separate multivariate analysis of patients with penetrating trauma also could not demonstrate a significant volume-mortality association (p = 0.919). Both regression models exhibited excellent discrimination and acceptable calibration. CONCLUSION: The findings of this study do not support the position that higher trauma center volumes are associated with improved survival. The implication of this study is that the hospital volume criteria established by the American College of Surgeons may need to be reexamined.