Probiotics/Synbiotics to Reduce Infectious Complications after Colorectal Surgery: A Systematic Review and Meta-Analysis of Randomised Controlled Trials.

AIM: The aims of this systematic review and meta-analysis were to assess to what extent probiotics/synbiotics reduce infectious complications after colorectal surgery and whether probiotics or synbiotics should be considered as perioperative measures preventing or reducing infectious complications after CRS and should be included in enhanced recovery programmes (ERP). Secondary aims were to answer practical questions precisely on the best formulation and the type and timing of probiotics or synbiotics in CRS.

METHOD: This systematic review and quantitative meta-analysis were conducted in accordance with PRISMA 2020 guidelines. Inclusion criteria were randomised trials comparing perioperative probiotics/synbiotics with a placebo or standard care in elective colorectal surgery. Exclusion criteria were non-randomised trials. Overall infectious complications and surgical site infections (SSIs including both deep abdominal infections and wound (skin or under the skin) infections) were the primary outcomes. Secondary outcomes were pulmonary and urinary infections, wound infections, and anastomotic leaks. The databases consulted were Medline, Cochrane Database of Systematic Reviews, Scopus, and Clinical Trials Register. Risk of bias was assessed according to the GRADE approach. The analysis calculated the random effects estimates risk ratio (RR) for each outcome.

RESULTS: 21 trials were included; 15 evaluated probiotics, and 6 evaluated synbiotics. There were significantly fewer infectious complications (risk ratio (RR) 0.59 [0.47-0.75], I2 = 15%) and fewer SSI (RR 0.70 [0.52-0.95], I2 = 0%) in the probiotic or synbiotic group. There were also significantly fewer pulmonary infections (RR 0.35 [0.20-0.63]) and urinary infections RR 0.41 [0.19-0.87]) as opposed to anastomotic leaks (RR 0.83 [0.47-1.48]) and wound infections (RR 0.74 [0.53-1.03]). Sensitivity analyses showed no significant difference between probiotics and synbiotics in reducing postoperative infections (RR 0.55 [0.42-0.73] versus RR 0.69 [0.42-1.13], p = 0.46).

CONCLUSIONS: Based on the finding of this study, probiotics/synbiotics reduce infectious complications after colorectal surgery. The effect size was more pronounced for pulmonary and urinary infections. From a practical aspect, some of the questions related to formulations and duration of probiotics or synbiotics need to be answered before including them definitively in enhanced recovery after colorectal surgery programmes.