Interpreting comparative died of wounds rates as a quality benchmark of combat casualty care.

BACKGROUND The died of wounds (DOW) rate is cited as a measure of combat casualty care effectiveness without the context of injury severity or insight into lethality of the battlefield. The objective of this study was to characterize injury severity and other factors related to variations in the DOW rate. METHODS The highest monthly DOW (HDOW) and lowest monthly DOW (LDOW) rates from 2004 to 2008 were identified from analysis and casualty report databases and used to direct a search of the Joint Theater Trauma Registry. Casualties from the HDOW and LDOW were combined into cohorts, and injury data were analyzed and compared. RESULTS The HDOW rates were 13.4%, 11.6%, and 12.8% (mean, 12.6%), and the LDOW rates were 1.3%, 2.0%, and 2.7% (mean, 2.0%) (p < 0.0001). The HDOW (n = 541) and LDOW (n = 349) groups sustained a total of 1,154 wounds. Injury Severity Score was greater in the HDOW than the LDOW group (mean [SD], 11.1 [0.53] vs. 9.4 [0.58]; p = 0.03) as was the percentage of patients with Injury Severity Score of more than 25 (HDOW, 12% vs. LDOW, 7.7%; p = 0.04). Excluding minor injuries (Abbreviated Injury Scale score of 1), there was a greater percentage of chest injuries in the HDOW compared with the LDOW group (16.5% vs. 11.2%, p = 0.03). Explosive mechanisms were more commonly the cause of injury in the HDOW group (58.7% vs. 49.7%; p = 0.007), which also had a higher percentage of Marine Corps personnel (p = 0.02). CONCLUSION This study provides novel data demonstrating that the died of wounds rate ranges significantly throughout the course of combat. Discernible differences in injury severity, wounding patterns, and even service affiliation exist within this variation. For accuracy, the died of wounds rate should be cited only in the context of associated injury patterns, injury severity, and mechanisms of injury. Without this context, DOW should not be used as a comparative medical metric.