No impact of sex on surgical site infections in abdominal surgery: a multi-center study

Objective Male sex is controversially discussed as a risk factor for surgical site infections (SSI). The aim of the present study was to evaluate the impact of sex on SSI in abdominal surgery under elimination of relevant confounders. Methods Clinicopathological data of 6603 patients undergoing abdominal surgery from a multi-center prospective database of four Swiss hospitals including patients between 2015 and 2018 were assessed. Patients were stratified according to postoperative SSI and risk factors for SSI were identified using univariate and multivariate analysis. Results In 649 of 6603 patients, SSI was reported (9.8%). SSI was significantly associated with reoperation (22.7% vs. 3.4%, p < 0.001), increased mortality rate (4.6% vs. 0.9%, p < 0.001), and increased rate of length of hospital stay > 75th percentile (57.0% vs. 17.9%, p < 0.001). In univariate analysis, male sex was a significant risk factor for SSI (p = 0.01). In multivariate analysis including multiple confounders' such as comorbidities and perioperative factors, there was no association between male sex and risk of SSI (odds ratio (OR) 1.1 [CI 0.8-1.4]). Independent risk factors for SSI in multivariate analysis were BMI >= 30 kg/m(2) (OR 1.8 [CI 1.3-2.3]), duration of surgery > 75th percentile (OR 2.3 [1.8-2.9]), high contamination level (OR 1.3 [1.0-1.6]), laparotomy (OR 1.3 [1.0-1.7]), previous laparotomy (OR 1.4 [1.1-1.7]), blood transfusion (OR 1.7 [1.2-2.4]), cancer (OR 1.3 [1.0-1.8] and malnutrition (OR 2.5 [1.8-3.4]). Conclusion Under elimination of relevant confounders, there is no significant correlation between sex and risk of SSI after abdominal surgery.