Fecal microbiota transplant delivered via invasive routes in irritable bowel syndrome: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS: Irritable bowel syndrome (IBS) results in significant loss of quality of life. Management guidelines do not recommend fecal microbiota transplant (FMT) for IBS based on weak evidence as refined data is lacking. We performed a systematic review and meta-analysis to ascertain the pooled clinical outcomes of FMT in IBS, delivered via invasive routes. METHODS: Multiple databases were searched through January 2023 to identify studies that reported on FMT treatment in IBS by invasive routes. Standard meta-analysis methodology using the random-effects model was used. Heterogeneity was assessed by I(2)% and 95% predication interval. RESULTS: Five studies were included. As many as 377 IBS patients were assessed, of which 238 received FMT and 139 received placebo. One study used nasojejunal tubes, one esophagogastroduodenoscopy and three colonoscopy for FMT delivery. FMT via colonoscopy was performed as a one-time procedure instilled into the cecum. Two studies used 30 g of stool from a single universal donor and one study used 50–80 g of pooled donor feces. The pooled odds ratio of improvement in IBS symptoms with FMT was significantly better as compared to that of placebo OR = 2.9 (95% CI [1.6–5.2, I(2) = 62%, p < 0.001]). This was true for studies that exclusively used colonoscopy (OR = 2.1 [1.1–4.2, p = 0.04]). In the FMT arm, 10 patients (10.6%) reported abdomen pain and worsening of symptoms with bloating and six patients (6.3%) reported diarrhea. CONCLUSION: FMT delivered via invasive routes, especially colonoscopy, demonstrated significant improvement in IBS symptoms. A single FMT consisting of 30 g or more of single universal donor feces instilled into the cecum is the predominant modality. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12664-023-01373-5.