Clinical outcomes following mechanical plus oral antibiotic bowel preparation versus oral antibiotics alone in patients undergoing colorectal surgery

BACKGROUND: Despite growing evidence to support use of preoperative mechanical bowel preparation (MBP) plus oral antibiotic bowel preparation (OABP) compared with MBP alone or no bowel preparation before colorectal surgery, evidence supporting use of MBP plus OABP relative to OABP alone is lacking. This study aimed to investigate whether the addition of MBP to OABP was associated with improved clinical outcomes after colorectal surgery compared with outcomes following OABP alone. METHODS: Patients who underwent colorectal surgery and preoperative bowel preparation with either OABP alone or MBP plus OABP were identified using the American College of Surgeons' National Surgical Quality Improvement Program Colectomy Targeted Participant Use Data File for 2012–2015. Thirty‐day postoperative outcomes were compared, estimating the average treatment effect with propensity score matching and inverse probability‐weighted regression adjustment. RESULTS: In the final study population of 20 594 patients, 90·2 per cent received MBP plus OABP and 9·8 per cent received OABP alone. Patients who received MBP plus OABP had a lower incidence of superficial surgical‐site infection (SSI), organ space SSI, any SSI, postoperative ileus, sepsis, unplanned reoperation and mortality, and a shorter length of hospital stay (all P < 0·050). After propensity score matching and inverse probability‐weighted regression adjusted analysis, MBP plus OABP was associated with a reduction in superficial SSI, any SSI, postoperative ileus and unplanned reoperation (all P < 0·050). CONCLUSIONS: Use of MBP plus OABP before colectomy was associated with reduced SSI, postoperative ileus, sepsis and unplanned reoperations, and shorter length of hospital stay compared with OABP alone.