Significance of obesity on nutritional, immunologic, hormonal, and clinical outcome parameters in burns

Abstract

Objective: The potential additive effect of obesity on selected nutritional, immunologic, hormonal, and clinical outcome parameters was evaluated.

Design: Fifteen obese patients were randomly matched for age, percentage of burn, percentage of third-degree burn, and inhalation injury to 15 nonobese patients.

Setting: Subjects were admitted to Shriners Burns Institute or University Hospital in Cincinnati, Ohio.

Results: The results of this study established a significant relationship between obesity and morbidity. Incidence of infection was greatest in the obese group (P < .03). Bacteremia (P < .008) and clinical sepsis (P < .005) occurred concomitant with obesity. The obese group required significantly (P < .05) more days on mechanical ventilatory support. Exogenous insulin supplementation (obese = 14.5 +/- 5.3 days, nonobese = 6.2 +/- 2.2 days) and antibiotic therapy (obese = 8.5 +/- 2.3 days, nonobese = 3.4 +/- 1.5 days) were required more than twice as many days in the obese group, although these trends did not reach statistical significance. Resting energy expenditure measurements were significantly higher in the obese group during weeks 1 (P < .0006) and 2 (P < .02), and the trend continued into weeks 3 and 4. Transferrin values for the obese group remained suppressed throughout the first 4 weeks after the burn, whereas the transferrin levels of the nonobese group were normal by week 4. Compared with normal-weight burn patients, obese burn patients had markedly lower alpha 2-macroglobulin values and higher glucagon levels throughout the study period.

Applications/conclusions: The data demonstrate the many metabolic and biochemical aberrations associated with obesity, distinct from the burn injury itself, and suggest that the overweight burn patient is at increased risk of morbidity. Given the prevalence of obesity in the United States, greater attention clearly needs to be given to its prevention and management.