OBESITY ASSOCIATED WITH INCREASED MORTALITY AND HOSPITAL LENGTH OF STAY IN TRAUMA LAPAROTOMY PATIENTS

Objectives: Although obesity in trauma patients is accepted as a risk factor for post-operative complications, recent literature describes conflicting evidence regarding the effect of BMI on mortality in trauma patients undergoing laparotomy. To address this question, we examined the patient population of a Level 1 Trauma Center to compare mortality rates between BMI groups in trauma patients undergoing laparotomy.

Methods: The trauma registry at an academic Level 1 Trauma Center was queried for the following criteria: age 19 or older, admission between 1/1/2017-1/1/2020, and laparotomy occurrence. The data was then stratified based on BMI (World Health Organization classification: < 18.5, 18.5-24.9,25-29.9, 30-39.9, and >40 corresponding to underweight, normal, overweight, obese, and morbidly obese respectively), mortality, injury severity score (ISS), and hospital length of stay (hLOS). Electronic medical records were reviewed in a retrospective manner in accordance with a protocol approved by our institutional review board. Logistic regression was used to assess the effect of BMI class on the probability of mortality. Linear regression was used to assess the effect of BMI class on LOS and ISS. In all models, BMI class was treated as an ordered factor. All analyses were performed using the R statistical software package (V.4.1.3, the R Foundation for Statistical Computing).

Results: There were 444 patients included in this analysis, with mean age 44.5 (SD=18.6) and mean BMI 28.59 (SD=7.39). In examining mortality based on BMI, we found that the odds ratio for death multiplies by 1.3, or increases 30%, for each increase in BMI class (p=.045, 95CI=1.00-1.58). Similarly, ISS increased by 1.3 points per each step up in BMI class (p=0.013, 95CI- 0.272-2.32). Additionally, hLOS increased by 8% for each increase in BMI class (p=0.04, 95CI= 0.3-16.6); after excluding patients who died during hospitalization, hLOS increased by 12% for each successive BMI class (p=.002, 95CI= 4.1-20.3).

Conclusion: At this institution, mortality, ISS, and hLOS significantly increase with higher BMI class in trauma patients undergoing laparotomy.