93 The BMI Paradox in Burn Patients

Abstract

Despite the fact that obesity is a known risk factor for comorbidities and complications, there is evidence suggesting a survival advantage for patients classified by body mass index (BMI) as overweight or obese. Investigated in various clinical areas, this “BMI paradox” has yet to be explored in the burn patient population. We sought to clarify whether this paradigm exists in burn patients. Data collected on 519 adult patients admitted to an American Burn Association/American College of Surgeons Verified Burn Center between 2009 and 2017 was utilized. Univariable and multivariable logistic regression were used to determine the association between in-hospital mortality and the National Heart, Lung and Blood Institute(NIH) BMI classifications (underweight <18.5 kg/m2, normal 18.5–24.9 kg/m2, overweight 25–29.9 kg/m2, obesity class I 30–34.9 kg/m2, obesity class II 35–39.9 kg/m2 and extreme obesity >40 kg/m2). The mean BMI of inpatients treated for burns was 29.56 (SD 10.64). For every kg/m2 increase in BMI, the odds of death decreased, with an adjusted odds ratio 0.82 (95% CI 0.71–0.96; p<0.01). When adjusted for total burn surface area, being in the obese class I rather than the normal classification was associated with an adjusted odds ratio of mortality of 0.032 (95% CI 0.0012 - 0.92; p<0.05), whereas having a BMI >40 kg/m2 had an odds ratio of 0.00. The adjusted odds ratio if underweight was 12.11 (95%CI 1.55–94.62; p<0.05). There was no statistically significant difference in odds of mortality between a normal and an overweight BMI. The “BMI paradox” exists in burn care. Further investigation is needed to elucidate what specific phenotypic aspects confer this benefit and how these can enhance the care of burn patients. Alters understanding of predictors of outcome.