S1567 The Impact of Fecal Microbiota Transplantation on Refractory Ulcerative Colitis: A Systematic Review and Meta-Analysis of Randomised Controlled Trials

Introduction: Refractory ulcerative colitis (UC), characterized by persistent disease activity despite optimized medical therapy, poses a significant therapeutic challenge. Fecal microbiota transplantation (FMT) has shown promise in inducing remission in active UC by restoring gut microbial balance, but its efficacy in refractory cases remains unclear. This systematic review and meta-analysis aimed to evaluate the efficacy and safety of FMT in achieving clinical and endoscopic remission in patients with refractory UC, based on evidence from randomized controlled trials (RCTs). Methods: We searched PubMed, Scopus, Google Scholar Cochrane CENTRAL, and Web of Science up to February 2025 for RCTs comparing FMT to placebo or standard care in adults with refractory UC (Mayo Score ≥3 despite treatment). Primary outcomes were clinical remission (Mayo Score ≤2, no subscore >1) and endoscopic remission (Mayo endoscopic subscore ≤1). Data were pooled using a random-effects model, with heterogeneity assessed via I² and Q-tests. Subgroup analyses explored age at diagnosis and disease duration as moderators. The review followed PRISMA guidelines and was registered with PROSPERO (CRD420250651790). Results: Six RCTs were included. FMT showed no significant effect on clinical remission (pooled estimate -0.2584; 95% CI, -0.9031 to 0.3863; P = 0.4321) or endoscopic remission (pooled estimate -0.2229; 95% CI, -0.8811 to 0.4353; P = 0.5069), with no heterogeneity (I² = 0.00%). Subgroup analyses revealed no moderation by age or disease duration (P > 0.27). Adverse events were mild and transient. Conclusion: FMT does not significantly improve clinical or endoscopic remission in refractory UC, suggesting limited efficacy in this population despite a favorable safety profile. Larger, standardized trials are warranted.