Urinary Biomarkers are Associated with Severity and Mechanism of Injury

Combat-related blast trauma results in massive tissue injury and tends to involve multiple systems. Further, an acute measure of injury severity based on underlying biological mechanisms may be important for the triage and treatment of these types of patients. We hypothesized that urinary biomarkers (UBs) would reflect severity of injury and that they would be elevated for blast injuries compared with gunshot wounds (GSW) in a cohort of combat casualties. We also postulated that UBs would be higher in patients with burns compared with patients with non-burn trauma in a civilian cohort. Among 80 service members who sustained combat-related injuries, we performed generalized estimating equations to compare differences in log-transformed concentrations of the UBs by both injury severity and injury mechanism. Among 22 civilian patients, we performed Kruskal-Wallis tests to compare differences for the UBs stratified by burn and non-burn trauma. In the military cohort, with the exception of IL-18, all UBs were significantly (P <0.05) higher for patients with a severe combat-related injury (Injury Severity Score ≥25). In addition, all crude UBs concentrations were significantly higher for blast versus GSW patients (P < 0.05). After adjusting for injury severity score and time of UB draw, KIM-1 (2.80 vs. 2.31; P = 0.03) and LFABP (-1.11 vs.-1.92; P = 0.02) were significantly higher for patients with a blast mechanism of injury. There were no significant differences in UBs between burn and non-burn civilian trauma patients. Future studies are needed to understand the physiologic response to trauma and the extent that UBs reflect these underlying processes.