{Reference Type}: Journal Article {Title}: All trauma is not created equal: Redefining severe trauma for combat injuries. {Author}: Lammers DT;Marenco CW;Morte KR;Bingham JR;Martin MJ;Eckert MJ; {Journal}: Am J Surg {Volume}: 219 {Issue}: 5 {Year}: 05 2020 {Factor}: 3.125 {DOI}: 10.1016/j.amjsurg.2020.03.020 {Abstract}: Injury severity scores (ISS) and shock index (SI) are popular trauma scoring systems. We assessed ISS and SI in combat trauma to determine the optimal cut-off values for mortality and trauma outcomes. Retrospective analysis of the Department of Defense Trauma Registry, 2008-2016, was performed. Areas under receiver operating characteristic curves (AUROCs) were calculated for ISS and SI on mortality, massive volume transfusion (MVT), and emergent surgical procedure (ESP). Optimal cut-off values were defined using the Youden index (YI). 22,218 patients (97.1% male), median ages 25-29 years, ISS 9.4 ± 0.07, with 58.1% penetrating injury were studied. Overall mortality was 3.4%. AUROCs for ISS on mortality, MVT, and ESP were 0.882, 0.898, and 0.846, while AUROCs for SI were 0.727, 0.864, and 0.711 respectively. The optimal cut-off values for ISS on mortality, MVT, and ESP were 12.5 (YI = 0.634), 12.5 (YI = 0.666), and 12.5 (YI = 0.819), with optimal values for SI being 0.94 (YI = 0.402), 0.88 (YI = 0.608), and 0.81 (YI = 0.345) respectively. Classic values for severe ISS underrepresent combat injury while the SI values defined in this study are consistent with civilian data.