A multivariate analysis of the factors associated with wound infection after colorectal surgery

Wound infection has been proposed as a key indicator of clinical outcome after colorectal surgery. The aim of this study was to identify risk factors that were associated with wound infections in patients undergoing either emergency or elective colonic resections.

We prospectively evaluated 251 patients admitted to Royal Perth Hospital over a 12-month period. All patients received prophylactic peri-operative antibiotics and were reviewed for 6 weeks post-operatively. Wound infection was defined as either the presence of pus or a serous discharge containing pathogenic bacteria. We evaluated the relationship between 40 independent variables and the incidence of wound infection.

There were 124 males and 127 females, of median age 68 years (range 14-90 years). The overall incidence of wound infection was 12%. Multiple logistic regression identified the presence of shock (odds ratio (OR) 14.6, P=0.05), atelectasis (OR 3.9, P=0.02), and number of days on antibiotics before surgery (OR 1.2, P=0.02) as significant independent variables.

These results suggest that the factors which were most often associated with wound infection were those that are indicative of either extensive disease or poor general health. The presence of a stoma and colonic perforation were not strong independent associations with wound infection.