Bowel Preparation for Colorectal Procedures: A Review of Clinical Effectiveness, Cost-Effectiveness and Guidelines

Evidence at high risk for bias, using incidence of surgical site infection from two RCTs, suggests that there is benefit to adding MBP to intravenous antibiotics and that there is no benefit to adding oral antibiotics to intravenous antibiotics. Because of the poor quality of these studies, confidence in these findings is low. The incremental benefit of adding both MBP and oral antibiotics to intravenous antibiotics is unknown, as no RCTs making those comparisons were identified.

There was no relevant evidence identified that would inform the cost-effectiveness of parenteral prophylaxis with oral antibiotics and/or mechanical bowel preparation.

Four guidelines recommend the use of mechanical bowel preparation plus oral antibiotic before colorectal surgery, and three of these guidelines recommend intravenous antibiotic prophylaxis in the context of colorectal surgery. One guideline suggests that MBP is not required, but oral antibiotics are recommended in the context of colon resection for sigmoid diverticulitis. Two guidelines explicitly recommend against the use of MBP without oral antibiotics. One guideline explicitly stated that no recommendation could be made regarding the use of MBP plus oral antibiotics in children because most of the available data are from studies of adults.

The data upon which the guidelines were based had the same limitations as the RCT evidence relevant for this review. The data upon which the recommendations were made lacked RCTs that used intravenous antibiotics alone as a comparator. Therefore, while the guidelines recommended both MBP and oral antibiotic prophylaxis, these recommendations did not stem from a knowledge of the incremental benefit associated with adding MBP and oral antibiotics to intravenous antibiotics.