Mechanism of Injury Differentiates Risk Factors for Mortality in Geriatric Trauma Patients

To evaluate the relationship between mechanism of injury and mortality in geriatric trauma patients and the ability of existing injury severity indices (ISIs) to assess mortality.

Retrospective review.

Urban level 1 trauma center.

Four thousand five hundred forty-five trauma patients age ≥55 presenting between 2008 and 2011.

Low-energy (LE-GTP) and high-energy (HE-GTP) geriatric trauma patient cohorts were created based on ICD-9 injury codes. Existing ISIs were evaluated for their ability to predict in-hospital mortality using the area under the receiver-operating characteristic curve (AUROC).

Mortality.

The Trauma Score-Injury Severity Score (TRISS) was the most predictive ISI for both cohorts and was deemed to have moderate predictive capacity (AUROC: 0.82) in LE-GTP and excellent predictive capacity (AUROC: 0.91) in the HE-GTP. For, HE-GTP each 1-year increase in age was associated with a 12% increase risk of mortality versus 6% for LE-GTP. Preexisting conditions (PECs) were distributed differently between the cohorts with significantly more PECs in the LE-GTP (P < 0.01).

Existing ISIs have fair-to-moderate predictive capacity for in-hospital morality in LE-GTPs and moderate-to-excellent predictive capacity in HE-GTPs. LE-GTPs and HE-GTPs are distinct cohorts that should be evaluated separately. Combining the cohorts underestimates both the effect of age on HE-GTPs and the effect of PECs on LE-GTPs while overestimating the effect of PECs on HE-GTPs.

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.