The New Injury Severity Score: a more accurate predictor of in-hospital mortality than the Injury Severity Score

J Trauma. 2004 Jun;56(6):1312-20. doi: 10.1097/01.ta.0000075342.36072.ef.


Objective: The purpose of this study was to determine whether the New Injury Severity Score (NISS) is a better predictor of mortality than the Injury Severity Score (ISS) in general and in subgroups according to age, penetrating trauma, and body region injured.

Methods: The study population consisted of 24,263 patients from three urban Level I trauma centers in the province of Quebec, Canada. Discrimination and calibration of NISS and ISS models were compared using receiver operator characteristic (ROC) curves and Hosmer-Lemeshow statistics.

Results: NISS showed better discrimination than ISS (area under the ROC curve = 0.827 vs. 0.819; p = 0.0006) and improved calibration (Hosmer-Leme-show = 62 vs. 112). The advantage of the NISS over the ISS was particularly evident among patients with head/neck injuries (area under the ROC curve = 0.819 vs. 0.784; p < 0.0001; Hosmer-Lemeshow = 59 vs. 350).

Conclusion: The NISS is a more accurate predictor of in-hospital death than the ISS and should be chosen over the ISS for case-mix control in trauma research, especially in certain subpopulations such as head/neck-injured patients.

Publication types

  • Comparative Study
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Area Under Curve
  • Craniocerebral Trauma / mortality
  • Female
  • Hospital Mortality*
  • Humans
  • Injury Severity Score*
  • Male
  • Middle Aged
  • Quebec / epidemiology
  • ROC Curve
  • Registries
  • Sensitivity and Specificity
  • Spinal Injuries / mortality
  • Wounds and Injuries / mortality*