EP340 - Ileus After Colorectal Surgery: An Early Sign of Clostridioides difficile Infection?

Purpose/Background: Clostridioides difficile infection is an important cause of post-operative morbidity and mortality in colorectal surgery (CRS) patients. Timely diagnosis can be confounded by the overlap of signs and symptoms of CDI with expected post-operative abdominal pain and altered bowel function. While ileus is often expected after colorectal surgery, it may also be a sign of developing CDI. Indeed, nasogastric tube (NGT) use has been identified as a potential risk factor for CDI in previous studies, but data on this have been inconsistent. More work is needed to determine whether ileus after CRS is associated with diagnosis of CDI.

Methods/Interventions: This retrospective analysis of the National Surgical Quality Improvement Program (NSQIP) database included United States adults who underwent colectomies between 2017-2023, as defined by CPT code. Rates and trends of CDI were analyzed with a generalized linear model. Bivariate associations between ileus rates and CDI were evaluated with chi-squared tests for each year and for the entire population. Multivariable logistic regression models were created to evaluate risk factors for CDI in this population and covariates included ileus, age, race, sex, ASA class, steroid use, disseminated cancer, preoperative functional status, HbA1c, albumin, creatinine, smoking status, mechanical bowel prep, and preoperative oral antibiotics. Statistical significance was defined as p< 0.05.

Results/Outcomes: 307,541 colectomy patients were included. Overall, the rate of CDI was 1.02%, which decreased slightly from 1.33% in 2017 to 0.84% in 2023 (-0.077%/year, p=0.0004). The average age of the population was 62 years old and 52% were female. On adjusted analysis, not including ileus, risk factors for CDI in this population included increased age, female sex, White race, normal HbA1c, elevated creatinine, lower preoperative functional status, and absence of preoperative PO antibiotics.

The population of colectomy patients overall had an ileus rate of 16%. Rates of ileus were statistically significantly associated with CDI (Chi-Square=575, p< 0.0001) on unadjusted analysis. Patients who were reported to have early (POD < 15) CDI had an ileus rate of 36% (n=2,072). In patients who were reported to have late (POD15-30) CDI, the rate of ileus was 25% (n=1,051). There was a statistically significant association between early vs. late CDI and ileus rates (Table 1). When added to the multivariable logistic regression model, ileus remained statistically significantly associated with CDI (OR=2.26, p< 0.01).

Conclusion/Discussion: Our analysis of 307,541 patients revealed a slight decrease in CDI rates over time among patients undergoing colorectal surgery. While notable, this is somewhat difficult to interpret given the limitations of database analysis. In patients undergoing colectomy, there is a clear association between ileus development and the diagnosis of CDI. Early postoperative CDI appears to be more highly associated with ileus development than later postoperative CDI. Colonization by Clostridioides difficile and subsequent development of CDI may present as slow return of bowel function and development of ileus. Further research will be needed to clarify the temporality of the relationship between C. difficile status and ileus. This may lead to more clarity and allow for earlier diagnosis and prompt treatment of CDI after colon resection.

Table 1
Table 1. Comparing rates of ileus among colectomy patients who developed CDI, looking at both early (POD <15) and late (POD15-30) presentations of CDI (Columns A & B). Rate of ileus among patients who developed CDI (Column C). Rate of ileus among all colectomy patients included in the analyses (Column D). Percentage are column percentages.