UNCORRECTED PROOF Validating the Injury Severity Score (ISS) In Different Populations: ISS Predicts Mortality Better Among Hispanics and Females Q1 O. B. Bolorunduro,* C. Villegas,† T. A. Oyetunji,* E. R. Haut,† K. A. Stevens,† D. C. Chang,* E. E. Cornwell III,* D. T. Efron,† and A. H. Haider† ,1 *Trauma Outcomes Research Group, Department of Surgery Howard University College of Medicine, Washington, DC; and †Center for Surgery Trials and Outcomes Research, Department of Surgery Johns Hopkins University School of Medicine, Baltimore, Maryland Submitted for publication January 9, 2010 Introduction. The Injury Severity Score (ISS) is the most commonly used measure of injury severity. The score has been shown to have excellent predictive ca- pability for trauma mortality and has been validated in multiple data sets. However, the score has never been tested to see if its discriminatory ability is af- fected by differences in race and gender. Objective. This study is aimed at validating the ISS in men and women and in three different race/ethnic groups using a nationwide database. Methods. Retrospective analysis of patients age 18– 64 y in the National Trauma Data Bank 7.0 with blunt trauma was performed. ISS was categorized as mild (<9,) moderate (9–15), severe (16–25), and profound (>25). Logistic regression was done to measure the rel- ative odds of mortality associated with a change in ISS categories. The discriminatory ability was compared using the receiver operating characteristics curves (ROC). A P value testing the equality of the ROC curves was calculated. Age stratified analyses were also con- ducted. Results. A total of 872,102 patients had complete data for the analysis on ethnicity, while 763,549 pa- tients were included in the gender analysis. The over- all mortality rate was 3.7%. ROC in Whites was 0.8617, in Blacks 0.8586, and in Hispanics 0.8869. Hispanics have a statistically significant higher ROC (P value < 0.001). Similar results were observed within each age category. ROC curves were also significantly higher in females than in males. Conclusion. The ISS possesses excellent discrimina- tory ability in all populations as indicated by the high ROCs. Ó 2010 Published by Elsevier Inc. Key Words: trauma; ISS (injury severity score); scor- ing systems; outcomes. INTRODUCTION Trauma is the leading cause of morbidity and mortal- ity in young adults [1]. In 2006, unintentional injury accounted for over 52,000 deaths among patients aged between one and 45 y in the United States [2]. A de- tailed understanding of two major factors is essential to predict clinical outcomes post-trauma: the severity of injury [3–5] and the patient’s physiologic reserve [6]. A patient’s reserve is a composite measure of the influence of age, gender, co-morbidities, insurance, complications, and other unmeasured factors that alto- gether explain why each patient is different from the other. This paper focuses on the measurement of injury severity in different populations and how this predicts outcomes. Several scoring methods are used to assess injury severity; they are divided into anatomic, physiologic, and combined scoring systems. Anatomic systems in- clude ISS, New Injury Severity Score (NISS), and Man- gled Extremity Severity Score (MESS). Examples of physiologic scores are the Glascow Coma Score (GCS) and Revised Trauma Score (RTS). The ASCOT (A Severity Characterization of Trauma) and Trauma Related Injury Severity Score (TRISS) are examples of combined scoring systems [1, 3. 6–8].The Injury Severity Score (ISS) is the foremost and gold standard test for assessing injury severity [11, 26]. It was developed to measure the severity of injury based on 1 To whom correspondence and reprint requests should be addressed at Center for Surgery Trials and Outcomes Research (CSTOR) and Division of Trauma, Department of Surgery, Johns Hop- kins School of Medicine, 600 N. Wolfe Street, Carnegie 683, Baltimore, MD 21287. E-mail: ahaider1@jhmi.edu. 0022-4804/$36.00 Ó 2010 Published by Elsevier Inc. 1 FLA 5.0 DTD  YJSRE10220_proof  6 May 2010  1:25 am  ce Journal of Surgical Research -, 1–6 (2010) doi:10.1016/j.jss.2010.04.012 ARTICLE IN PRESS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105