Comparison of alternative methods for assessing injury severity based on anatomic descriptors.

BACKGROUND: There is mounting confusion as to which anatomic scoring systems can be used to adequately control for trauma case mix when predicting patient survival.
METHODS: Several Abbreviated Injury Scale (AIS) and International Classification of Disease Clinical (ICD-9CM)-based methods of scoring severity were compared by using data from the Pennsylvania Trauma Outcome Study. By using a design dataset, the probability of survival was modeled as a function of each score or profile. Resulting coefficients were used to derive expected probabilities in a test dataset; expected and observed probabilities were then compared by using standard measures of discrimination and calibration.
RESULTS: The modified Anatomic Profile, Anatomic Profile, and New Injury Severity Score outperformed the International Classification of Disease-based Injury Severity Score. This finding remains true when AIS values are obtained by means of a conversion from International Classification of Disease to AIS.
CONCLUSION: Results support the integrity of the AIS and argue for its continued use in research and evaluation. The modified Anatomic Profile, Anatomic Profile, and New Injury Severity Score, however, should be used in preference to the Injury Severity Score as an overall measure of severity.