The effect of mechanical bowel preparation on anastomotic leaks in elective left-sided colorectal resections

•We evaluate the association between bowel preparation and anastomotic leaks.•In all, 5,481 patients underwent an elective colon resection with left-sided anastomosis.•A total of 2,581 (57%) patients received bowel preparation, whereas 1,935 (43%) patients did not.•Thirty-day anastomotic leak rate with and without bowel preparation was 3.1% and 5.1%.•Bowel preparation omission was associated with a higher rate of anastomotic leaks.

BackgroundRoutine preoperative mechanical bowel preparation (MBP) for left-sided colorectal resections remains controversial. This study aims to evaluate the association between MBP and 30-day anastomotic leaks.MethodsA retrospective cohort study was conducted using data from the National Surgical Quality Improvement Program from 2011 to 2012. Multiple imputation was used for missing data, and a multivariable logistic regression was performed to adjust for clinically relevant variables. A propensity score–adjusted model was performed as a sensitivity analysis.ResultsA total of 2,581 patients (57%) received preoperative MBP, whereas 1,935 (43%) did not. The 30-day anastomotic leak rate with and without preoperative MBP was 3.1% and 5.1%, respectively. After covariate adjustment, MBP omission was significantly associated with a 40% increased odds of 30-day anastomotic leaks (odds ratio 1.41, P = .04, 95% confidence interval 1.01 to 1.93).ConclusionsMBP omission was associated with a higher rate of 30-day anastomotic leaks. A large, well-designed, randomized controlled trial is needed to further evaluate this relationship.