The New Injury Severity Score (NISS) was proposed in 1997 to replace the Injury Severity Score (ISS) because it is more sensitive for mortality. We aim to test whether this is true in our patients.
This study was a retrospective review of data from 6,231 consecutive patients over 3 years in the trauma registry of a Level I trauma center studying outcome, ISS, and NISS.
Misclassification rates were 3.97% for the NISS and 4.35% for the ISS. The receiver operating characteristic curve areas were 0.936 and 0.94, respectively. Neither the ISS nor the NISS were well calibrated (Hosmer-Lemeshow statistic, 36.11 and 49.28, respectively; p < 0.001).
The NISS should not replace the ISS, as they share similar accuracy and calibration.
From the Department of Emergency Medicine, University of Illinois at Chicago (S.Y.-T., E.P.S.), and Departments of Emergency Medicine (L.Z.) and Trauma Surgery (P.Z.), Mount Sinai Hospital, Chicago, Illinois.
Submitted for publication July 15, 2002.
Accepted for publication January 13, 2003.
Address for reprints: Seow-Yian Tay, MB, BS, FRCS(Ed)(A&E), FAMS, Department of Emergency Medicine, Tan Tock Seng Hospital, Moulmein Road, 387980 Singapore; email: firstname.lastname@example.org.