Yu Jin Kim

Objective Motorcyclists face a higher risk of severe morbidity and mortality compared to automobile passengers. This study aimed to determine the injury characteristics of motorcyclists according to their body mass index (BMI). Methods A retrospective observational cross‐sectional study was conducted using data from the Emergency Department‐based Injury In‐depth Surveillance (EDIIS) registry. Motorcycle riders aged 18 or older who were injured and admitted to study hospitals between 2019 and 2020 were included. Patients were divided into three groups based on BMI cutoffs of 18.5 and 25 kg/m 2 : the low, optimal, and high BMI groups. The primary outcome was anatomical injury location according to the abbreviated injury scale. The secondary outcomes were the surgery and intensive care unit admission rate, and the 48‐h and 30‐day in‐hospital mortality. Multivariable logistic regression analysis was performed to assess the impact of BMI on outcomes. Results Among 1280 patients, the low and high BMI groups had higher risk of abdominal injuries (AIS ≥ 2) than the optimal BMI group, with adjusted odds ratios of 2.82 (95% CI 1.41–5.63) and 1.61 (95% CI 1.17–2.21), respectively. Only the low BMI group had a significant association with severe abdominal injury (AIS ≥ 3), with an adjusted odds ratio of 3.11 (95% CI 1.31–7.39). No significant association was found between BMI and surgery, ICU admission, or mortality. Conclusion The low BMI group was more likely to have an abdominal injury (AIS score ≥2 or AIS score ≥3) during motorcycle injuries. BMI was not associated with surgery, ICU admission, or mortality.