Faecal microbiota transplant offers no relief for IBS

Patients with irritable bowel syndrome (IBS) derive no clear benefit from faecal microbiota transplant (FMT), according to a recent study.

The meta-analysis included eight randomized trials, contributing a total of 472 patients. FMT was performed in 288 patients, while the remaining 184 were designated as controls. Most included studies measured FMT efficacy in terms of the 1-month change in IBS symptom severity score (IBS-SSS), while safety was generally assessed according to the development of nausea, abdominal pain, and diarrhoea. [Health Sci Rep 2022;5:e814]

Pooled analysis showed no significant effect of FMT on the 1-month change in IBS-SSS as compared with control (mean difference [MD], –10.55, 95 percent confidence interval [CI], –99.37 to 78.28; p=0.82). This analysis had significant heterogeneity (p<0.0001), which was resolved after removing one outlier study (p=0.23). Nevertheless, FMT bore no significant benefit to IBS patients (MD, 30.28, 95 percent CI, –11.14 to 71.70; p=0.15).

Similarly, the 3- or 4-month change in IBS-SSS was not significantly affected by FMT (MD, 22.05, 95 percent CI, –78.94 to 123.03; p=0.67). This analysis was also statistically heterogenous (p=0.0007), but the researchers could not resolve the issue.

Overall, FMT continued to bear no significant impact on IBS-SSS (MD, –3.04, 95 percent CI, –81.65 to 75.57; p=0.94). Heterogeneity also remained unresolved after the leave-one-out method (p<0.00001).

FMT likewise remained ineffective when assessed according to the number of patients who achieved a ≥50-point decrease in IBS-SSS (risk ratio [RR], 1.12, 95 percent CI, 0.44–2.83; p=0.82) and the number of treatment responders (RR, 1.84, 95 percent CI, 0.82–2.65; p=0.19).

Nevertheless, recipients of FMT showed a statistically significant improvement in quality of life scores (MD, 9.32, 95 percent CI, 4.08–14.55; p=0.0005) as compared with baseline. Such a benefit was apparent as soon as 1 month after intervention (MD, 7.044, 95 percent CI, 2.26–12.62; p=0.005).

“Although it may show a transient effect in some patients, this effect wears off drastically over time, and even after repeated administration, it does not show the initial effect, which suggests that it is only a placebo effect,” the researchers said.

Does route of administration play a role?

Researchers then conducted a subgroup analysis to assess whether the route of FMT administration affected its efficacy. They found similarly null impacts when the intervention was delivered through colonoscopy (RR, 0.77, 95 percent CI, 0.54–1.10; p=0.16) or through the nasojejunal route (RR, 2.12, 95 percent CI, 0.94–4.71; p=0.06).

However, there was a statistically significant correlation between FMT intervention and the number of treatment responders when delivered orally (RR, 2.03, 95 percent CI, 1.25–3.31; p=0.004) or through a gastroscope (RR, 3.49, 95 percent CI, 2.47–4.94; p<0.00001).

In terms of safety, FMT induced significantly greater abdominal pain (RR, 3.73, 95 percent CI, 1.57–7.23; p=0.002), diarrhoea (RR, 3.87, 95 percent CI, 1.29–11.59; p=0.02), and constipation (RR, 5.77, 95 percent CI, 1.63–20.42; p=0.007) than controls. No such effect was reported for bloating and nausea.

“Future studies should be directed toward probiotics and newer technologies in modulating gastrointestinal tract bacterial composition, as well as diet modification,” the researchers said. “Integrated management for IBS patients is now strongly advised as it addresses all pathological aspects of the disease.”