Simplifying Physiologic Injury Severity Measurement for Predicting Trauma Outcomes¹

Background: The Revised Trauma Score (RTS) is commonly used to assess physiologic injury; however its use is limited by missing data. This study compares different parameters of physiologic injury assessment in their ability to predict mortality after trauma. Methods: Adult patients in the National Trauma Data Bank (NTDB version 7.0) were analyzed, and the following physiologic injury parameters were compared: RTS, systolic blood pressure (SBP), shock (SBP ≤ 90 mm Hg), Glasgow coma scale-total (GCS-T), and GCS-motor (GCS-M). Areas under the receiver-operating characteristic curves (AUROC) were calculated for unadjusted and multivariate regression models to predict mortality after trauma. Results: There were 1,484,648 patients who met inclusion criteria. In unadjusted analyses, RTS had the highest proportion of missing data (21%) and was highly predictive of mortality (AUROC = 0.85). SBP and shock had a much lower AUROC of 0.67 and 0.66, respectively, but had many fewer missing cases. The combination parameters of GCS-M with SBP or GCS-M with shock showed AUROC comparable to RTS (0.85) with approximately 80,000 fewer missing cases. Conclusion: The discriminatory power of RTS is significantly better than SBP, shock, or GCS alone. Given the limitation of missing data associated with RTS, the combination of SBP and GCS-M is a more reliable and equally effective method of assessing physiologic injury severity in studying trauma outcomes.