Does obesity affect outcomes of adult burn patients?

Abstract

Background: Obesity negatively affects outcomes after trauma and surgery; results after burns are more limited and controversial. The purpose of this study was to determine the effect of obesity on clinical and economic outcomes after thermal injury.

Methods: The National Inpatient Sample was queried for adults from 2005-2009 with International Classification of Diseases-9 codes for burn injury. Demographics and clinical outcomes of obese and nonobese cohorts were compared. Univariate and multivariate analysis using logistic regression models were performed. Data are expressed as median (interquartile range) or mean ± standard deviation and compared at P < 0.05.

Results: In 14,602 patients, 3.3% were obese (body mass index ≥30 kg/m(2)). The rate of obesity increased significantly by year (P < 0.001). Univariate analysis revealed significant differences between obese and nonobese patients in incidence of wound infection (7.2% versus 5.0%), urinary tract infection (7.2% versus 4.6%), deep vein thrombosis in total body surface area (TBSA) ≥10% (3.1% versus 1.1%), pulmonary embolism in TBSA ≥10% (2.3% versus 0.6%), length of stay [6 d (8) versus 5 d (9)], and hospital costs ($10,122.12 [$18,074.72] versus $7892.07 [$17,191.96]) (all P < 0.05). Death occurred less frequently in the obese group (1.9% versus 4%, P = 0.021). Significant predictors of grouped adverse events (urinary tract infection, wound infection, deep vein thrombosis, and pulmonary embolism) on multivariate analysis include obesity, TBSA ≥20%, age, and black race (all P ≤ 0.05).

Conclusions: Obesity is an independent predictor of adverse events after burn injury; however, obesity is associated with decreased mortality. Our findings highlight the potential clinical and economic impact of the obesity epidemic on burn patients nationwide.

Keywords: BMI; DVT; Morbidity; Mortality; Obesity; Outcomes; Overweight; PE; TBSA; Thermal injury.