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

Abstract

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. 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). 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). 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.