# Skeletal Muscle Quality Evaluation for Prognostic Stratification in the Emergency Department of Patients ≥65 Years with Major Trauma

## TL;DR

This study shows that measuring muscle quality via CT scans in elderly trauma patients can help predict their risk of death during hospitalization.

## Contribution

The study introduces CT-based skeletal muscle density as a novel prognostic tool for elderly trauma patients in the emergency department.

## Key findings

- Lower skeletal muscle area density (SMAd) was significantly associated with higher mortality in elderly trauma patients.
- SMAd <38 HU at ED admission was an independent risk factor for in-hospital death.
- Low SMAd also increased the risk of death after the first week of hospitalization among survivors.

## Abstract

Background: In patients aged 65 years and older who experience severe trauma, their underlying health status significantly influences overall mortality. This study aimed to determine whether computed tomography (CT) evaluation of skeletal muscle quality could serve as an effective risk stratification tool in the emergency department (ED) for this population. Methods: Retrospective observational study conducted between January 2018 and September 2021, including consecutive patients ≥65 years admitted to the ED for a major trauma (defined as having an Injury Severity Score > 15). Muscle quality analysis was made by specific software (Slice-O-Matic v5.0, Tomovision®, Montreal, QC, Canada) on a CT-scan slice at the level of the third lumbar vertebra (L3). Results: A total of 263 patients were included (72.2% males, median age 76 (71–82)), of whom 88 (33.5%) died during hospitalization. The deceased patients had a significantly lower skeletal muscle area density (SMAd) compared with survivors. The multivariate Cox regression analysis confirmed that SMAd <38 at the ED admission was an independent risk for death (adjusted HR 1.68 [1.1–2.7]). The analysis also revealed that, among the survivors after the first week of hospitalization, the patients with low SMAd had an increased risk of death (adjusted HR 3.12 [1.2–7.9]). Conclusions: Skeletal muscle density assessed by a CT scan at ED admission may represent a valuable prognostic marker for risk stratification patients ≥65 years with major trauma. In patients with SMAd <38 HU the in-hospital mortality risk could be particularly increased after the first week of hospitalization.