Surgical site infections after abdominal surgery: incidence and risk factors. A prospective cohort study

Background: Abdominal surgeries have high rates of surgical site infections (SSIs), contributing to increased morbidity and mortality and costs for hospitalization. The aim of this study was to determine the SSI incidence rates and risk factors after abdominal surgeries. Methods: This prospective cohort study included all patients undergoing abdominal surgeries between 2005 and 2007 in the Western Galilee Medical Center in Nahariya, Israel. SSI incidence rates were calculated per 100 operations. Odds ratios (ORs) were estimated for each risk factor using univariate and multivariate analyses by logistic regression models. Results: Among 302 patients in the study cohort, the total SSI incidence rate was 22.2%. The univariate analysis defined 13 variables significantly associated with SSI: age >60 years, lower functional status, diabetes mellitus, congestive heart failure, immunocompromising underlying disease, treatment with chemotherapy and other immunosuppressive medications, impaired immune system open cholecystectomy, laparotomy, an American Society of Anesthesiologists (ASA) score >2, drain insertion, and 'dirty wound' classification. In multivariate regression analysis, treatment with immunosuppressive medications (OR = 2.5, 95% confidence interval (CI) = 1.099 - 143.443), open cholecystectomy (OR = 2.25, 95% CI = 2.242 - 40.109), and dirty wound classification (OR = 2.179, 95% CI = 3.80 - 20.551) were significantly associated with SSI. Conclusions: The significant risk factors defined should be addressed preoperatively to decrease the risk for SSI. Wound surveillance in the post-discharge period is necessary for correct estimation of SSI rates.