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


CONCLUSIONS
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.
Lavoie
André
A
Centre hospitalier affilié universitaire de Québec, Enfant-Jésus Hospital, Quebec City, Quebec, Canada. drlavoa@cha.quebec.qc.ca
Moore
Lynne
L
LeSage
Natalie
N
Liberman
Moishe
M
Sampalis
John S
JS
D000293:Adolescent; D000328:Adult; D000368:Aged; D019540:Area Under Curve; D006259:Craniocerebral Trauma / Q000401:mortality; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D015601:Injury Severity Score; D008297:Male; D008875:Middle Aged; D011792:Quebec / Q000453:epidemiology; D012372:ROC Curve; D012042:Registries; D012680:Sensitivity and Specificity; D013124:Spinal Injuries / Q000401:mortality; D014947:Wounds and Injuries / Q000401:mortality*