Increased incidence of nosocomial infections in obese surgical patients.

Obesity has long been considered a potential risk factor for poor outcome following surgical procedures. However, controversy exists regarding the clinical impact of this problem because of a paucity of data regarding the incidence and risk of nosocomial infections in obese surgical patients. This retrospective study was undertaken to compare the nosocomial infection rate in obese and normal weight surgical patients. All patients undergoing general, urologic, vascular, thoracic, or gynecologic surgical procedures between October 1 and December 31, 1991, were reviewed. Nosocomial infection data were obtained from the Department of Hospital Epidemiology. A total of 849 patients were evaluated, of which 536 (63%) were normal weight (BMI < 27 kg/m2), 175 (21%) were obese (BMI 27-31 kg/m2), and 138 (16%) were severely obese (BMI > 31 kg/m2). Age, mortality, and American Society of Anesthesia (ASA) risk scores did not differ among the three groups. There were significant increases in the number and percent of nosocomial infections in the obese populations, with rates of 0.05 per cent in normal weight, compared to 2.8 per cent and 4.0 per cent in obese and severely obese groups (P < 0.01). Infections consisted of seven wound infections, five C. difficile infections, one pneumonia, and three bacteremias. No differences in distribution between groups were evident. Mortality was similar among the groups. These data support the hypothesis that obesity is a significant risk factor for clinically relevant nosocomial infections in surgical patients.