Not All Cuts Heal the Same: Elevated Anastomotic Leak Rates after Elective Colectomy for IBD and Diverticulitis.

Background: Anastomotic leak is a severe complication of colorectal surgery. The association of anastomotic leak with indication for surgery remains unclear. This study aims to assess the risk of anastomotic leak among patients undergoing elective colectomy for inflammatory bowel disease, cancer, diverticulitis, and polyp, hypothesizing the highest risk in inflammatory bowel disease.

Methods: We conducted a retrospective cohort study of patients who underwent elective colectomy with primary ileocolic or colo-colonic anastomosis from 2011 to 2021. The primary outcome was the occurrence of anastomotic leak. Secondary outcomes included rates of reoperation, non-operative interventional, and conservative treatment after anastomotic leak, timing of reoperation, and incidence of anastomotic leak after hospital discharge. Univariable analyses used ANOVA and chi-square tests with post hoc corrections. Multivariable logistic regression identified independent anastomotic leak risk factors. Kruskal-Wallis with Dunn's test assessed reoperation timing.

Results: Among 83,992 patients, surgery for inflammatory bowel disease (3.4%) and diverticulitis (3.0%) had higher rates of anastomotic leak compared with those undergoing surgery for colon cancer (2.3%) and polyps (2.0%) (p < 0.001). Multivariable analysis showed inflammatory bowel disease (OR 1.28 [95% CI 1.03-1.58]) and diverticulitis (1.20 [1.03-1.39]) were independently associated with anastomotic leak when compared with colon cancer. Patients with inflammatory bowel disease who developed anastomotic leak were more likely to undergo non-operative interventional treatment (32.4%) compared with colon cancer (18.5%) and polyp cohorts (23.8%).

Conclusion: Surgery for inflammatory bowel disease and diverticulitis are risk factors for anastomotic leak following elective colectomy, with inflammatory bowel disease having the highest risk.