Biological sex, but not obesity, independently predicts anatomical injury patterns in trauma bay patients: a multivariate retrospective analysis of 2,128 patients.

Abstract

Background: While sex-specific disparities in trauma outcomes are well established; the biological contribution of sex versus anthropometric variables like obesity in determining initial anatomical injury severity remains poorly understood. This study aimed to independently isolate the effect of biological sex on serious damage, while controlling for energy exposure and body factors.

Methods: A retrospective cohort study of 2,128 consecutive adult trauma bay patients (males: n = 1570; females: n = 558) was conducted. Univariate comparisons and multivariate binary logistic regression models were used to identify independent predictors of severe overall injury (Injury Severity Score [ISS] ≥ 9) and severe regional injuries (Abbreviated Injury Scale [AIS] ≥ 3), while controlling for age, body-mass-index (BMI) and obesity (BMI ≥ 30). Adjusted odds ratios (aOR) were calculated with 95% confidence intervals.

Results: Compared to females, males were significantly more likely to suffer High-Energy Trauma (HET) (p < 0.001) and had a higher overall injury severity (ISS ≥ 9) in univariate analysis. Male sex was found to be an independent predictor of significant injury in all adjusted models: ISS ≥ 9 (aOR = 1.33, p = 0.010), AIS ≥ 3 for thorax/spine (aOR = 1.38, p = 0.003), and AIS ≥ 3 for face (aOR = 1.78, p = 0.020). For ISS ≥ 9 (aOR = 1.27, p = 0.034) and AIS ≥ 3 thorax/spine (aOR = 2.40, p < 0.001), HET was an independent predictor. Neither dichotomous obesity (BMI ≥ 30) nor continuous BMI was a significant independent predictor of any injury outcome (all p ≥ 0.075), with odds ratios near unity (OR range: 0.978-1.017) indicating no dose-response relationship.

Conclusions: Biological sex and kinetic energy are the primary determinants for severe overall and regional trauma. Conversely, obesity does not independently affect initial anatomical injury severity. The lack of independent impact from obesity suggests that sexual dimorphism in biomechanics, skeletal geometry, and tissue resilience - rather than absolute obesity - underlies the increased vulnerability of males in acute trauma.