Treatment is a challenge in Irritable Bowel Syndrome (IBS) and fecal microbiota transplantation (FMT) has attracted significant interest. Network meta-analysis (NWM) has been established as an evidence-synthesis tool that incorporates direct and indirect evidence in a collection of randomized controlled trials (RCTs) comparing therapeutic intervention competing for similar therapeutic results. No NWM exists concerning the comparative effectiveness and safety of various FMT modalities for IBS.

We updated pairwise meta-analyses published in the past and assessed the comparative effectiveness and safety of various FMT delivery modalities for IBS.

Pairwise meta-analyses and Bayesian NWM were performed. Heterogeneity, consistency of results and publication bias were explored.

Of 510 titles raised by initial search, seven RCTs were entered into meta-analyses and NWM. They included 470 patients and controls, in whom four FMT delivery modalities were used, that is via colonoscopy, nasojejunal tube, duodenoscope and capsules per os. In the pairwise meta-analysis, the pooled results showed that overall FMT was not superior to placebo, whereas the subgroup analyses showed that FMT via duodenoscope and nasojejunal tube was superior. The NWM showed that 60-g FMT via duodenoscope had the highest efficacy (OR, 26.38; 95% CI, 9.22–75.51) and was by far the highest in the efficacy ranking (SUCRA, 98.8%).

The pooled results showed no overall advantage of FMT over placebo in IBS. However, upper GI delivery (via duodenoscopy or nasojejunal tube) proved to be effective. Consequently, well-designed RCTs are needed to ensure the efficacy and safety profile before FMT can be applied in everyday clinical practice for IBS patients.