Introduction
Functional dyspepsia (FD) is associated with duodenal eosinophilia and gut microbiota dysbiosis. Proton pump inhibitors (PPIs), as a first-line therapy, can suppress duodenal eosinophilic inflammation to ameliorate symptoms, yet the symptom relief rate is low. Rifaximin (RIF), an antibiotic known to modulate the gut microbiota, may offer an alternative therapeutic avenue. It is hypothesized that combining RIF with PPIs could more effectively alleviate FD symptoms and duodenal inflammation by targeting the gut microbiota.
Aims & Methods
A single-center, open-label, randomized controlled clinical trial was conducted on subjects who met the inclusion and exclusion criteria (Trial registration: ChiCTR2300069313). Ninety-six patients were randomly assigned in a 1:1 ratio to either the PPI+RIF group or the PPI group. The follow-up period extended to 4 weeks post-treatment cessation. The primary endpoint was the symptom relief rate, while secondary endpoints included symptom response rate, duodenal eosinophil counts, and changes in the microbiota. The study hypothesis was that the clinical efficacy of PPI+RIF would be superior to that of PPI monotherapy.
Results
| PPI+RIF
| PPI
| Z value
| P value
| PPI+RIF
| PPI
| Z value
| P value
|
|---|
Abbreviations: PPI+RIF: Proton Pump Inhibitor plus Rifaximin; PPI: Proton Pump Inhibitor; ITT: the intention-to-treat analysis;PP: the per-protocol analysis.
|
Symptom relief rate
| ITT
| PP
|
Week 2
| 54.2%(26/48)
| 54.2%(26/48)
| 0.000 | 0.500 | 53.7%(22/41) | 53.3%(24/45)
| 0.030 | 0.488 |
Week 4
| 72.9%(35/48)
| 58.3%(28/48)
| 1.522 | 0.064 | 76.7%(33/43)
| 56.8%(25/44)
| 2.020 | 0.022 |
4 weeks post-treatment
| 77.1%(37/48)
| 47.9%(23/48)
| 3.095 | 0.001 | 78.6%(33/42)
| 48.9%(22/45)
| 3.036 | 0.001 |
Symptom response rate
| ITT
| PP
|
Week 2
| 70.8%(34/48)
| 72.9%(35/48)
| -0.227
| 0.590
| 68.3%(28/41)
| 73.3%(33/45)
| -0.514
| 0.696
|
Week 4
| 81.3%(39/48)
| 77.1%(37/48)
| -0.503
| 0.307
| 83.7%(36/43)
| 75.0%(33/44)
| 1.012
| 0.156
|
4 weeks post-treatment
| 85.4%(41/48)
| 68.8%(33/48)
| 1.982
| 0.024
| 85.7%(36/42)
| 71.1%(32/45)
| 1.688
| 0.046
|
A total of 96 patients were enrolled in the randomized controlled study. There were no statistically significant differences in baseline demographic data and clinical characteristics between the two groups. According to the intention-to-treat (ITT) analysis, the PPI+RIF group showed significantly higher rates of symptom relief (
P = 0.001) and symptom response (
P = 0.024) at 4 weeks post-treatment. These findings were supported by the per-protocol (PP) analysis, which revealed a superior symptom relief rate for the combination group at both 4 weeks of treatment (
P = 0.022) and 4 weeks post-treatment (
P = 0.001), as well as a superior symptom response rate at 4 weeks post-treatment (
P = 0.046). Combination therapy also led to a greater reduction in duodenal eosinophil infiltration (
P = 0.036) and significantly decreased peak hydrogen sulfide (H₂S) levels (
P < 0.001), indicating a reduction in small intestinal bacterial load. Oral microbiota analysis revealed that β-diversity of the oral flora increased following the PPI+RIF intervention, with an increased relative abundance of
Enterococcus (
P = 0.004). Conversely, the PPI intervention led to the enrichment of the potentially pathogenic bacterium
Catonella (
P = 0.006). Notably, treatment responders in the PPI+RIF group showed a specific enrichment of the
Eubacterium_yurii_group (
P = 0.037), an alteration associated with the amelioration of duodenal eosinophilic inflammation and the enhancement of pathways related to preventing bacterial invasion of the epithelium.
Conclusion
In patients with FD, combining a PPI with Rifaximin is superior to PPI monotherapy, improving both symptoms and duodenal eosinophil infiltration. This effect is linked to a reduction in H₂S-producing bacteria and a beneficial shift in the oral microbiota. The oral abundance of Eubacterium_yurii_group may serve as a biomarker for treatment response.
Disclosure
The authors declare that they have no conflicts of interest.