A Comparative Study Between Two Combat Injury Severity Scores

Introduction: In recent years, specific trauma scoring systems have been developed for military casualties. The objective of this study was to examine the discrepancies in severity scores of combat casualties between the Abbreviated Injury Scale 2005-Military (mAIS) and the Military Combat Injury Scale (MCIS) and a review of the current literature on the application of trauma scoring systems in the military setting. Methods: A cross-sectional, descriptive, and retrospective study was conducted between May 1, 2005, and December 31, 2014. The study population consisted of all combat casualties attended in the Spanish Role 2 deployed in Herat (Afghanistan). We used the New Injury Severity Score (NISS) as reference score. Severity of each injury was calculated according to mAIS and MCIS, respectively. The severity of each casualty was calculated according to the NISS based on the mAIS (Military New Injury Severity Score-mNISS) and MCIS (Military Combat Injury Scale-New Injury Severity Score-MCIS-NISS). Casualty severity were grouped by severity levels (mild-scores: 1-8, moderate-scores: 9-15, severe-scores: 16-24, and critical-scores: 25-75). Results: Nine hundred and eleven casualties were analyzed. Most were male (96.37%) with a median age of 27 years. Afghan patients comprised 71.13%. Air medevac was the main casualty transportation method (80.13). Explosion (64.76%) and gunshot wound (34.68%) mechanisms predominated. Overall mortality was 3.51%. Median mNISS and MCIS-NISS were similar in nonsurvivors (36 [IQR, 25-49] vs. [IQR, 25-48], respectively) but different in survivors, 9 (IQR, 4-17) vs. 5 (IQR, 2-13), respectively (P < .0001). The mNISS and MCIS-NISS were discordant in 34.35% (n = 313). Among cases with discordant severity scores, the median difference between mNISS and MCIS-NISS was 9 (IQR, 4-16); range, 1 to 57. Conclusion: Our study findings suggest that discrepancies in injury severity levels may be observed in one in three of the casualties when using mNISS and MCIS-NISS.