The Impact of Obesity on the Outcomes of 1,153 Critically Injured Blunt Trauma Patients

BACKGROUND: Several small series have had mixed conclusions regarding the impact of obesity on outcomes of trauma patients. The purpose of the present study was to evaluate a large cohort of critically injured patients to better understand the influence of obesity on the outcomes of patients after severe blunt trauma. METHODS: Retrospective review using the trauma registry and intensive care unit (ICU) database of all blunt trauma patients admitted to the ICU at our urban, Level I trauma center over a 5-year period (1998-2003). Obese patients (body mass index BMI > or = 30 kg/m) were compared with non-obese patients (BMI < 30 kg/m). RESULTS: There were 1,153 blunt trauma patients admitted to the ICU during the study period, including 283 (25%) obese (mean BMI = 35 +/- 6 kg/m) and 870 (75%) non-obese (mean BMI = 25 +/- 3 kg/m) patients. There was no difference between groups regarding age, sex, Injury Severity Score, or admission vitals. Obese patients had fewer head injuries (42 versus 55%; p = 0.0001) but more chest (45 versus 38%; p = 0.05) and lower extremity (53 versus 38%; p < 0.0001) injuries. There was no difference in the need for laparotomy, thoracotomy, or craniotomy. Obese patients suffered more complications (42 versus 32%; p = 0.002). Although there was only a trend toward higher mortality in obese patients (22 versus 17%; p = 0.10), stepwise logistic regression revealed obesity as an independent risk factor for mortality (odds ratio, 1.6; 95% confidence interval, 1.0-2.3; p = 0.03). Among survivors, obese patients required longer stays in the hospital (24 +/- 21 versus 19 +/- 17 days; p = 0.01), the ICU (13 +/- 14 versus 10 +/- 10 days; p = 0.005), and 2 more days of mechanical ventilation (8 +/- 13 versus 6 +/- 9 days; p = 0.07). CONCLUSION: Obese patients incur different injuries after severe blunt trauma than their non-obese counterparts. Despite sustaining fewer head injuries, obese patients suffer more complications, require longer stays in the hospital, more days of mechanical ventilation, and obesity is independently associated with mortality.