# Mechanical and oral antibiotics bowel preparation reduce the risk of surgical site infections and anastomotic leakage in colorectal surgery: a GRADE-based meta-analysis and trial sequential analysis

## TL;DR

Using mechanical and oral antibiotics bowel preparation before colorectal surgery reduces surgical site infections and anastomotic leakage, according to a meta-analysis of randomized trials.

## Contribution

This study provides robust evidence that combining mechanical and oral antibiotics bowel preparation reduces surgical complications in colorectal surgery.

## Key findings

- MOABP significantly reduces surgical site infections with moderate-quality evidence.
- MOABP also significantly reduces anastomotic leakage with moderate-quality evidence.
- Subgroup analyses show reductions in various types of surgical site infections.

## Abstract

Recent updates from randomized controlled trials (RCTs) indicated that mechanical and oral antibiotics bowel preparation (MOABP) can reduce post-operative surgical site infection (SSI), but its effect on anastomotic leakage (AL) remains controversial. This study systematically reviews and conduct trial sequential analysis (TSA) of the RCTs to determine whether MOABP can reduce SSI and AL after colorectal surgery.

We conducted a comprehensive search of PubMed, Cochrane Library, Embase, and Web of Science for RCTs comparing MOABP to mechanical bowel preparation (MBP) alone, from database inception to February 1, 2025. Study quality was assessed using the Cochrane Risk of Bias tool. Meta-analysis, subgroup analysis, and sensitivity analysis were conducted using RevMan 5.3.1 software. TSA was performed with TSA software to evaluate the robustness of the primary outcomes.

A total of 17 RCTs involving 4,633 patients were included. Meta-analysis showed that the MOABP significantly reduced SSI (OR = 0.44, 95% CI: 0.37–0.54, p < 0.00001, I2 = 33%, moderate-quality evidence) and AL (OR = 0.42, 95% CI: 0.30–0.57, p < 0.00001, I2 = 3%, moderate-quality evidence). Subgroup analyses indicated reductions in superficial SSI, deep SSI, space and organ infection. TSA further confirmed the robustness of these findings.

MOABP can effectively reduce the risk of SSI and AL in colorectal surgery. Pre-operative bowel preparation should consider incorporating oral antibiotics to optimize surgical outcomes.

https://www.crd.york.ac.uk/PROSPERO/recorddashboard.