L. A. De Leon Castro1, E. A. Alore1, J. W. Suliburk1, C. T. Wilson1, M. A. Davis1, S. R. Todd1 1Baylor College Of Medicine,Surgery,Houston, TX, USA
Introduction: The effect of body mass index (BMI) on penetrating injuries is not well described. The aim of this study was to describe the effect of BMI on the severity of penetrating injuries by abbreviated injury score (AIS). We hypothesized that increasing BMI would be protective against higher injury severity in patients with penetrating mechanisms.
Methods: This was a retrospective analysis of penetrating trauma patients ≥ 16 years old from the 2007-2015 National Trauma Data Bank (NTDB). Patients transferred, dead on arrival, or with isolated brain injury were excluded. Patients were classified by BMI category as underweight (<18.99kg/m2), normal (19-24.99kg/m2), overweight (25-29.99kg/m2), obese (30-39.99kg/m2), and morbidly obese (≥40kg/m2). AIS severity was defined as minor (AIS 1-3) or major (AIS 4-6). Univariate and multivariate analyses were performed to assess association with BMI (significance, p<0.05).
Results: 83,826 patients were evaluated. The median age was 30 (IQR 23-41); 87% were men. Median BMI was 25.9 kg/m2 (IQR 23-30). The mechanism of injury was stab wound in 43% and firearm in 57%. The median AIS by region was 2 (IQR 1-3) for the abdomen, 3 (IQR 1-3) for the thorax, and 1 (IQR 1-2) for the extremities. The median injury severity score (ISS) was 5 (IQR 1-11). Overall mortality was 5.3%. On univariate analysis by BMI category, AIS severity was not significant for the abdomen (p=0.316), thorax (p=0.267), or extremities (p=0.184). This lack of significance continued when analyzed by mechanism of injury: stab wound – abdomen (p=0.350), thorax (p=0.471), or extremities (p=0.074); firearm – abdomen (p=0.172), thorax (p=0.340), or extremities (p=0.318). On multivariate analysis, AIS severity was not associated with BMI category for the abdomen (p=0.729), thorax (p=0.226), or extremities (p=0.232). Variables significantly associated with AIS severity were systolic blood pressure (abdomen: OR=0.986, CI=0.984-0.987, p<0.001; thorax OR=0.984, CI=0.982-0.985, p<0.001; extremities OR=0.977, CI=0.973-0.980, p<0.001), heart rate (abdomen: OR=1.008, CI=1.006-1.010, p<0.001; thorax OR=1.004, CI=1.002-1.006, p<0.001; extremities OR=1.021, CI=1.017-1.025, p<0.001) and firearm mechanism of injury (abdomen: OR=7.548, CI=6.562-8.681, p<0.001; thorax OR=2.223, CI=2.006-2.463, p<0.001; extremities OR=13.873, CI=8.752-21.992, p<0.001). Mortality did not vary significantly (p=0.552) across BMI categories.
Conclusion: Increased BMI is not associated with protection from penetrating injuries. Mortality did not vary significantly across BMI categories.