Comparison of manual and computer assigned injury severity scores.

Background: The study objective was to compare the ISS manually assigned by hospital personnel and those generated by the ICDPIC software for value agreement and predictive power of length of stay (LOS) and mortality.

Methods: We used data from the 2010-2016 trauma registry of a paediatric trauma centre (PTC) and 2014 National Trauma Data Bank (NTDB) hospitals that reported manually coded ISS. Agreement analysis was performed between manually and computer assigned ISS with severity groupings of 1-8, 9-15, 16-25 and 25-75. The prediction of LOS was compared using coefficients of determination (R) from linear regression models. Mortality predictive power was compared using receiver operating characteristic (ROC) curves from logistic regression models.

Results: The proportion of agreement between manually and computer assigned ISS in PTC data was 0.84 and for NTDB was 0.75. Analysing predictive power for LOS in the PTC sample, the R=0.19 for manually assigned scores, and the R=0.15 for computer assigned scores (p=0.0009). The areas under the ROC curve indicated a mortality predictive power of 0.95 for manually assigned scores and 0.86 for computer assigned scores in the PTC data (p=0.0011).

Conclusions: Manually and computer assigned ISS had strong comparative agreement for minor injuries but did not correlate well for critical injuries (ISS=25-75). The LOS and mortality predictive power were significantly higher for manually assigned ISS when compared with computer assigned ISS in both PTC and NTDB data sets. Thus, hospitals should be cautious about transitioning to computer assigned ISS, specifically for patients who are critically injured.