Michigan Journal of Medicine

Introduction

The Injury Severity Score (ISS) and New Injury Severity Score (NISS) are known predictors of outcomes such as mortality, ICU admission, and hospital length of stay^1-7. However, these calculations only use the three highest Abbreviated Injury Scale (AIS) scores and do not include information about other sustained injuries^5,6. It is unclear if incorporating the total count of the patient’s injuries would help in predicting post-discharge utilization. Further, specific body region injury categories (e.g., musculoskeletal) may affect discharge outcomes more than others. In this study, we quantified the number of patient injuries that were not included in the NISS calculation and evaluated whether these “missed” injuries predict discharge destination.

Methods

Data from a statewide trauma quality improvement program from 1/1/2015-12/31/2022 was utilized. Adult patients (≥18yrs) were included, and those that died during admission were excluded. The number of total injuries in each AIS body region subcategory was counted. We assessed the total number of injuries for each patient that was not included in the NISS calculation and an ANOVA to assess missed injuries across NISS categories. A multivariable logistic regression controlling for NISS and other trauma-related covariates was performed to evaluate the likelihood of a patient being discharged to a rehabilitation facility.

Results

There were 211,949 patients that met inclusion criteria with a mean of 1.33±2.5 injuries not included after the NISS was calculated. With increasing NISS categories, there was a significant increase in the mean number of injuries not included (NISS 5-15: 0.62 injuries±1.36; NISS 16-24: 2.57±2.81; NISS 25-35: 4.24±4.31; NISS>35: 6.05±4.73, p<0.001). The number of extremity, abdominal, chest, and head/neck injuries and higher NISS categories were associated with an increased likelihood of being discharged to a rehabilitation facility. (Table)

Tables & Figures

References

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