eP741 - Development of a Risk Stratification Tool to Predict Surgical Site Infections After Colorectal Surgery: A Michigan Surgical Quality Collaborative Study

Purpose/Background: The colon contains trillions of live luminal bacteria, including multiple human pathogens. Colorectal operations are clean-contaminated, contaminated, or dirty cases with an inherent risk of surgical site infections (SSI) at a rate of 10-30%. SSI are the most common postoperative complication after colorectal surgery, and cause significant patient suffering as well as a substantial economic burden. Healthcare-associated infections are a common cause of morbidity and mortality in hospitals. Surgical site infections can contribute to prolonged hospital stays, increased readmission and intervention rates. Surgical admissions complicated by a SSI have a 1.5 fold increase in readmission rates within 30 days, a twofold increase in unplanned return to the operating room and a twofold increase in initial hospital costs. SSI have a 3% mortality rate after colorectal resection. This study aims to identify preoperative and perioperative factors to predict the risk of developing an SSI in order to minimize the prevalence.Methods/Interventions: This is a retrospective study utilizing the Michigan Surgical Quality Collaborative (MSQC) database. Following an institutional review board approval, all patients undergoing an elective colorectal operation between 2018-2021 were included. Patients' demographics, comorbidities and technical aspects of the operations were extracted. The cohorts with and without surgical site infections were compared for differences in demographics, clinical characteristics and intraoperative findings using a bivariate analysis. Chi-square or Fisher’s exact test were used to compare proportions. The data were tested for normality and homogeneity of variance. Student’s t test was used for analysis of normally distributed continuous variables. In order to identify independent predictors of postoperative surgical site infections, a forward stepwise logistic regression was performed adjusting for variables that were different in the univariate analysis at p < 0.05. Adjusted odds ratios and 95% confidence intervals were derived from the regression.Results/Outcomes: A total number of 3142 patients were included. SSI occurred in 5.1% of the patient population. A univariate analysis identified age, sex, body mass index, a history of obstructive sleep apnea, a history of deep vein thrombosis, tobacco use, the need to place drains, the presence of an ostomy, a minimally invasive surgical approach and wound classification at the conclusion of the case were identified as being associated with development of surgical site infections. Logistic regression analysis identified age, the presence of DVT, the need to place intracavitary drains, and dirty wound classification as independently associated with development of surgical site infections.Conclusion/

Discussion: Historically, colorectal surgery has always been touted as an outlier, with high SSI rates being justified by the nature of the surgery. Recent data from the CDC demonstrated that SSI represent 22% of all healthcare infections and approximately 15% are associated with colorectal surgery. In our study, the prevalence of SSI was 5.1% and the majority of them were deep organ space infections (64%). As a result, striving to reduce SSI rates after colorectal operations is a high priority for surgical quality improvement. The outcomes of this retrospective study further solidify common risk factors that contribute to the development of SSI after colorectal surgery."Table 1.

Patient demographics
Table 2.

Clinical characteristics of the patient population
Table 3.

Procedural details of the colorectal operations
Table 4.

Stepwise forward logistic regression identified the need to use drains, the creation of ostomy, age and history of DVT as being independently associated with the development of postoperative surgical site infections.
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