Risk factors for postoperative infectious complications in noncolorectal abdominal surgery: a multivariate analysis based on a prospective multicenter study of 4718 patients

Abstract

Hypothesis: Infectious complications are the main causes of postoperative morbidity in abdominal surgery. Identification of risk factors, which could be avoided in the perioperative period, may reduce the rate of postoperative infectious complications.

Design: A database was established from 3 prospective, randomized, multicenter studies. Multivariate analysis was performed using nonconditional logistic regression expressed as an odds ratio (OR).

Setting: Multicenter studies (ie, private medical centers, institutional hospitals, and university hospitals).

Patients: From June 1982 to September 1996, a database was established containing the information of 4718 patients who underwent noncolorectal abdominal surgery.

Main outcome measures: The dependent variables studied included surgical site infection (SSI) (divided into parietal and deep infectious complications with or without fistulas) and global infectious complications (SSI and extraparietal and abdominal infectious complications).

Results: The rate of global infectious complications was 13.3%; SSI, 4.05%; parietal infectious complications, 2.2%; deep infectious complications with fistulas, 2.18%; and deep infectious complications without fistulas, 1.38%. In multivariate analysis, the following 7 independent risk factors for global infectious complications have been identified: age (60-74 years, OR, 1.64; >or=75 years, OR, 1.45); being underweight (OR, 1.51); having cirrhosis (OR, 2.45), having a vertical abdominal incision (OR, 1.66); having a suture placed or an anastomis of the bowel (OR, 1.48) in the digestive tract; having a prolonged operative time (61-120 minutes, OR, 1.66; 121 minutes, OR, 2.72); and being categorized as having a class 4 surgical site (ie, obese patients or having a risk factor of a healing defect) (OR, 1.66). Ceftriaxone sodium therapy was identified as a protective factor (OR, 0.43). In multivariate analysis, the following 5 independent risk factors for SSI have been identified: the existence of a preoperative cutaneous abscess or cutaneous necrosis (OR, 4.75), having a suture placed or an anastomosis of the bowel (OR, 1.82) in the digestive tract, having postoperative abdominal drainage (OR, 2.15), undergoing a surgical procedure for the treatment of cancer (OR, 1.74), and receiving curative anticoagulant therapy (OR, 3.33) postoperatively.

Conclusions: Our data show that risk factors for SSI and for global infectious complications are disparate. Indeed, only the placement of a suture or having an anastomosis of the bowel in the digestive tract is a risk factor for both SSI and global infections. Some of these factors may be modifiable before or during the surgical procedure to reduce the infection rate or to prevent postoperative complications.