Measuring injury severity: time for a change?

Area of Science:

• Trauma research
• Medical scoring systems
• Injury assessment

Background:

• The Injury Severity Score (ISS) has limitations in assessing trauma severity, particularly with multiple injuries in the same body region.
• The New Injury Severity Score (NISS) considers the three most severe injuries irrespective of body region, potentially offering a more accurate trauma severity measure.

Purpose of the Study:

• To evaluate and compare the accuracy of the Injury Severity Score (ISS) and the New Injury Severity Score (NISS) in patients with blunt trauma.
• To determine which scoring system, ISS or NISS, better predicts short-term mortality.

Main Methods:

• A cohort of 2,328 blunt trauma patients treated between 1992 and 1996 was analyzed.
• The ISS and NISS were calculated for each patient to identify discrepancies.
• Receiver operating characteristic (ROC) curves were used to compare the predictive accuracy of ISS and NISS for short-term mortality in discrepant cases.

Main Results:

• The NISS (mean 33 ± 18) was higher than the ISS (mean 25 ± 13).
• Scores were identical in 32% of patients and discrepant in 68%.
• NISS demonstrated superior prediction of short-term mortality (Area Under Curve [AUC] 0.852 vs. 0.799; p < 0.001), with greater discrepancies correlating with higher mortality rates.

Conclusions:

• The NISS provides a more accurate prediction of short-term mortality in blunt trauma patients compared to the ISS.
• While NISS offers improved accuracy, potential disadvantages include the disruption of established scoring systems.
• Further research may explore greater improvements in trauma scoring systems.