Remission rates and safety of fecal microbiota transplantation in inflammatory bowel disease in adult patients: A systematic review

Background: Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn’s disease (CD), is a chronic gastrointestinal disorder that substantially impairs quality of life. Conventional therapies are often limited by suboptimal efficacy, adverse effects, and diminishing response over time. Fecal microbiota transplantation (FMT) has emerged as a therapeutic strategy aimed at restoring microbial balance, reducing inflammation, and improving outcomes. Objectives: To systematically evaluate clinical remission rates and safety profiles of FMT in IBD. Design: A systematic review of randomized controlled trials, controlled clinical trials, and observational studies, reported in accordance with the PRISMA-2020 guideline. Data sources and methods: Searches were conducted in Google Scholar (November 17, 2024) and Scopus (November 19, 2024). Eligible studies included randomized controlled trials, controlled clinical trials, and observational studies published after 2015 that reported remission and/or safety outcomes in adult IBD patients. Reviews, protocols, pediatric or animal studies, non-English publications, and non-peer-reviewed sources were excluded. Risk of bias was assessed using an adapted Cochrane approach, with common concerns relating to blinding and subjective outcome assessment. Results: From 309 records, 22 studies met inclusion criteria. Mean remission rates were 46.6% for FMT via colonoscopy (41.75% for CD and 47.17 for UC), and 58.13% for alternative routes (capsules, enemas, tubes), yielding an overall mean remission of 47.61%. Adverse events were generally mild gastrointestinal symptoms; serious events were rare, including infections and procedure-related complications. Conclusion: FMT, particularly via colonoscopy, appears effective and generally safe for IBD. However, heterogeneity in donor selection and protocols, limited long-term data, and English-language restriction constrain generalizability. Larger, standardized, and longer-term trials are needed to consolidate evidence. Trial registration: This study was registered post-study at INPLASY registration number: INPLASY202620020, and no formal protocol was prepared; conducted as a coursework project but adhered to prespecified criteria and PRISMA-2020 reporting. Consequently, no amendments were made to the information provided at registration or in the protocol.