Beneficial Impacts of pre- and Postoperative Probiotics/Synbiotics Supplementation in Patients Undergoing Gastrointestinal Surgeries: An Umbrella Meta-Analysis.

Probiotics and synbiotics may help reduce complications following gastrointestinal (GI) surgeries by restoring microbial balance and modulating immune responses. This umbrella meta-analysis aimed to evaluate their effectiveness in improving pre- and postoperative outcomes. Following PRISMA guidelines, 17 meta-analyses were included after a comprehensive database search. Outcomes assessed included infection rates, hospital stay, diarrhea, mortality, and antibiotic use. Study quality was evaluated using the AMSTAR 2 tool. Pooled effect sizes were calculated using a random-effects model. Heterogeneity was quantified with the I² statistic and Cochrane's Q-test, and predefined subgroup analyses were conducted by intervention type, treatment duration, surgical complications, and patient condition. Sensitivity analyses evaluated result stability. Publication bias was assessed using funnel plots, Begg's and Egger's tests, with the trim-and-fill method applied where asymmetry was detected. Significantly reduced postoperative infections (OR = 0.48, 95% CI: 0.42-0.53), including surgical site infections, urinary tract infections, pulmonary infections, and sepsis. Supplementation also shortened hospital stays (SMD = - 0.95, 95% CI: - 1.79 to - 0.10), decreased the incidence of diarrhea (OR = 0.37, 95% CI: 0.23-0.50), lowered mortality (OR = 0.48, 95% CI: 0.13-0.82), and reduced antibiotic use duration (SMD = - 1.87, 95% CI: - 3.69 to - 0.05). Preoperative-only supplementation use was especially effective in liver surgeries and among patients under 60 years of age. The overall methodological quality was moderate to high in most included studies. Probiotic and synbiotic supplementation, particularly during the perioperative period, appears to be an effective strategy for reducing complications following gastrointestinal surgeries. These findings support their inclusion as adjunct therapies in enhanced recovery protocols.