Fecal Microbiota Transplant Delivery Method May Impact Benefit for Treatment of IBS

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Findings from a recent systematic review and meta-analysis are providing clinicians with an overview of the safety and efficacy of fecal microbiota transplantation (FMT) for the treatment of irritable bowel syndrome (IBS).¹

Although the overall pooled estimates did not show a significant benefit of FMT for IBS, subgroup analyses revealed FMT delivery through endoscopy, nasojejunal tube, or rectal enema had a greater impact on symptom improvement and quality of life. Additionally, greater benefit was observed in studies with a lower risk of bias.¹

“Although previous randomized controlled trials have evaluated the efficacy of FMT in IBS treatment, their results were inconsistent and limited by their small sample sizes. Prior systematic reviews with meta-analyses of RCTs also have some limitations,” Pei-Chun Lai, MD, of National Cheng Kung University Hospital in Taiwan, and colleagues wrote.¹

According to the American College of Gastroenterology, IBS affects approximately 10% to 15% of people in the United States. There is no cure for IBS and treatment is largely focused on lifestyle modifications with diet and stress. Certain medications have been shown to help relieve symptoms and aid bowel movement. FMT has been explored as a potential treatment option for IBS due to its known impact on gut microbiota, but its safety and efficacy have not been confirmed.^1,2

To evaluate the efficacy and safety of FMT for IBS based on available evidence, investigators searched Embase, MEDLINE, Cochrane CENTRAL, CINAHL, and Scopus for randomized controlled trials in human subjects that compared FMT with a control intervention in patients with IBS. For inclusion, studies were required to be a randomized controlled trial enrolling patients diagnosed with IBS by a clinician or based on specific criteria; have an intervention with FMT at any dosage and through any route of administration, and a control group treated with a placebo or autologous transfer; and have primary outcomes for clinical response and changes in the severity of IBS symptoms, including IBS-SSS and IBS-QOL scores, and secondary outcomes for the safety and side effects of the intervention.¹

Investigators assessed the quality of included studies using the revised Cochrane Risk-of-Bias tool for Randomized Trials. Additionally, the Grading of Recommendations Assessment Development and Evaluation (GRADE) methodology was used to assess the certainty of evidence.¹

The initial literature search yielded 639 potentially eligible articles, 576 of which investigators deemed to be unique and relevant after duplicate removal. After title, abstract, and full-text screening, 12 randomized controlled trials were ultimately included in the study. Collectively, these studies had a total of 615 participants, with 356 in the FMT group and 259 in the control group, and were published between 2018 and 2023.¹

The pooled effect showed no significant difference between the FMT and control groups in clinical response rate with high heterogeneity (relative risk [RR], 1.44; 95% CI, 0.88 to 2.33; I2 = 79%). Additionally, overall pooled estimates revealed no statistically significant difference in IBS Severity Scoring System (IBS-SS) or IBS Quality of Life (IBS-QOL) scores after 8-12 weeks between the FMT and control groups (standardized mean difference [SMD], − 0.31; 95% CI, − 0.72 to 0.09; I2 = 77% and SMD, 0.30; 95% CI, − 0.09 to 0.69; I2 = 68%).¹

Investigators conducted subgroup analyses and found the clinical response of the group that received FMT via endoscopy (colonoscopy and gastroscopy), nasojejunal tube, and rectal enema was superior to that of the control group with moderate heterogeneity (RR, 1.91; 95% CI, 1.26–2.91; I2 = 61%). They noted this benefit was also observed for IBS-SSS (SMD, − 0.43; 95% CI, − 0.73 to − 0.13; I2 = 43%) and IBS-QOL (SMD, 0.53, 95% CI, 0.20 to 0.86; I2 = 34%).¹

Investigators additionally pointed out pooled data from randomized controlled trials with a low risk of bias showed the FMT group was superior to the control groups for clinical response (RR, 3.53; 95% CI, 2.21–5.64; I2 = 0%), IBS-SSS (SMD, − 0.66; 95% CI, − 0.99 to − 0.33; I2 = 2%), and IBS-QOL (SMD, 0.77; 95% CI, 0.45–1.09; I2 = 0%).¹

Of note, the pooled analysis revealed no significant difference between the FMT and control groups in adverse events, including nausea, abdominal pain/cramping/tenderness, diarrhea, constipation, bloating/flatulence, and fever.¹

Investigators acknowledged multiple limitations to these findings, including the heterogeneity of the enrolled participants; the varying inclusion criteria for symptom severity across the included studies; and differences in FMT origin, dosage, therapy duration, frequency, comparators, and study protocols.¹

“This study revealed that while the overall pooled estimates did not show a significant benefit of FMT for IBS, subgroup analyses revealed that FMT delivered via routes with more direct delivery to the gut, such as endoscopy, nasojejunal tube, or rectal enema, and in well-designed studies, may be an effective treatment option for improving symptoms and quality of life in IBS patients,” investigators concluded.¹

References

1. ^{Lo SW, Hung TH, Lin YT, et al. Clinical efficacy and safety of faecal microbiota transplantation in the treatment of irritable bowel syndrome: a systematic review, meta-analysis and trial sequential analysis. Eur J Med Res. https://doi.org/10.1186/s40001-024-02046-5}
2. ^{American College of Gastroenterology. Irritable Bowel Syndrome (IBS). Accessed September 23, 2024. https://gi.org/topics/irritable-bowel-syndrome/#tabs1}