Characteristics of ACS-verified Level I and Level II trauma centers: A study linking trauma center verification review data and the National Trauma Data Bank of the American College of Surgeons Committee on Trauma.

BACKGROUND: The Trauma Quality Improvement Project of the American College of Surgeons (ACS) has demonstrated variations in trauma center outcomes despite similar verification status. The purpose of this study was to identify structural characteristics of trauma centers that affect patient outcomes.

METHODS: Trauma registry data on 361,187 patients treated at 222 ACS-verified Level I and Level II trauma centers were obtained from the National Trauma Data Bank of ACS. These data were used to estimate each center's observed-to-expected (O-E) mortality ratio with 95% confidence intervals using multivariate logistic regression analysis. De-identified data on structural characteristics of these trauma centers were obtained from the ACS Verification Review Committee. Centers in the lowest quartile of mortality based on O-E ratio (n = 56) were compared to the rest (n = 166) using Classification and Regression Tree (CART) analysis to identify institutional characteristics independently associated with high-performing centers.

RESULTS: Of the 72 structural characteristics explored, only 3 were independently associated with high-performing centers: annual patient visits to the emergency department of fewer than 61,000; proportion of patients on Medicare greater than 20%; and continuing medical education for emergency department physician liaison to the trauma program ranging from 55 and 113 hours annually. Each 5% increase in O-E mortality ratio was associated with an increase in total length of stay of one day (r = 0.25; p < 0.001).

CONCLUSIONS: Very few structural characteristics of ACS-verified trauma centers are associated with risk-adjusted mortality. Thus, variations in patient outcomes across trauma centers are likely related to variations in clinical practices.

LEVEL OF EVIDENCE: Therapeutic study, level III.