The risk of inflammatory bowel disease flares after fecal microbiota transplantation: Systematic review and meta-analysis

Twenty-nine studies with 514 FMT-treated IBD patients were included. Range of follow up was 4 weeks to 3 y. The pooled rate of IBD worsening was 14.9% (95% CI 10-21%). Heterogeneity was detected: I2 D 52.1%, Cochran Q test D 58.1, p D 0.01. A priori subgroup analyses were performed. Although not significant, the pooled rate of worsening in IBD activity following FMT for CDI (22.7% (95% CI: 13-36%)) was higher compared with FMT for IBD (11.1% (95% CI 7-17%)). Rates of worsening in IBD after lower GI FMT delivery revealed a higher rate of worsening in IBD activity (16.5% (95% CI: 11-24%)) compared with upper GI delivery (5.6% (95% CI: 2-16%)). Rates of worsening in high quality studies and randomized controls trials (RCTS) suggested a marginal risk of worsening in IBD activity (4.6%, (95% CI: 1.8-11%). Rates of IBD worsening are overall marginal across high quality RCTS. It is unknown if the FMT itself led to the worsening of IBD in this small fraction or if this represents alternative etiologies.