BMI is independently associated with ARDS, sepsis and multiorgan failure after major trauma—results of a high-volume retrospective observational cohort study

Abstract Background Obesity is increasingly prevalent among trauma patients and has been proposed to influence post-injury inflammatory responses and organ dysfunction. However, evidence on the independent effect of body mass index (BMI) on in-hospital complications after major trauma remains conflicting. This study aimed to determine whether BMI is an independent predictor of specific adverse clinical outcomes in a large cohort of adult trauma patients. Methods This retrospective cohort study analyzed associations between BMI and adverse clinical outcomes (ARDS, pneumonia, sepsis, multiorgan failure (MOF) and mortality) among adult trauma patients at a German level-I trauma center between 2018 and 2024. Inclusion criteria were trauma leading to an Injury Severity Score (ISS) ≥ 9 and/or admission to the intensive care unit. Multivariable logistic regression adjusted for BMI, age, sex, ASA and ISS. Results A total of 1514 patients were included. Adjusted multivariate regression revealed BMI as being independently associated with an increased risk of ARDS (aOR 1.09 per kg/m 2 , 95% CI 1.01–1.16; p = 0.025), sepsis (aOR 1.05, 95% CI 1.00–1.10; p = 0.048) and MOF (aOR 1.10, 95% CI 1.04–1.17; p 30 kg/m 2 ) as a clinically relevant non-linear cut-off point. Conclusions A higher BMI was independently associated with ARDS, sepsis and MOF, but no independent association with mortality was detected in this cohort of adult trauma patients. This suggests that BMI may function as a clinically relevant risk marker.