A case-control study of risk factors for wound infection in a colorectal unit

Postoperative wound infections have been responsible for increasing morbidity and are associated with an increased use of hospital resources. Previous studies have identified several risk factors. However, most studies are outdated, and few relate to the era of enhanced recovery and laparoscopic surgery. This study investigated the association between patient and operative factors and the development of postoperative wound infections in colorectal surgery.

Patients with documented wound infections or dehiscences were identified from a database of elective and emergency colorectal surgery. Patients with wound infections were matched by operation type to a control group of colorectal patients. Differences in patient and operative factors between case and control group were analysed using conditional logistic regression.

A total of 56 patients with wound infection were identified from 647 operations (8.6%). Fifty-seven per cent were emergency operations and eighty-eight per cent were performed as open surgery or as laparoscopic surgery converted to open. Forty per cent of patients had high ASA (American Society of Anesthesiologists) grades (3 or 4). Multivariate logistical regression showed that obese patients and those having open surgery had the highest risk of infections. The median postoperative hospital stay for patients with wound infections was twice as long as for those patients without wound infections.

Open surgery and obesity are independent risk factor for wound infections. An increase in laparoscopically performed operations and new strategies for managing wounds in obese patients may help to reduce the rate of wound infection.