Risk factors for infectious complications after abdominal surgery for malignant disease

The emergence of nosocomial infection as a serious complication after intraabdominal operations for cancer prompted us to identify major independent risk factors associated with postoperative infection.

Risk factors were studied in single and multivariate analyses. Variables considered were remote infection, antimicrobial prophylaxis, preoperative stay, chemotherapy, radiotherapy, weight loss, elective versus emergency operation, wound class, duration of operation, drains, sex, age, and physical status.

During 24 months, 236 patients were entered in the study. The overall postoperative infection rate was 45.7%; the surgical site infection rate was 22.4%. Multivariate analysis identified three independent variables: duration of operation longer than 5 hours (odds ratio 6.41, 95% confidence interval 3.28 to 12.54), presence of remote infection at operation (odds ratio 3.76, 95% confidence interval 1.76 to 8.03), and preoperative stay longer than 22 days (odds ratio 2.03, 95% confidence interval 1.04 to 3.95). The relative risk of infection increased from 3.0 when one risk factor was present to 7.3 when all three risk factors were present.

The predictive power of our final multivariate risk index clearly groups these patients according to differing risk for postoperative infection. This classification contributes substantially to the effectiveness of infection control strategies to prevent the occurrence of postoperative infection in the high-risk population of patients with cancer.