A Longitudinal Study to Identify IBS Phenotypes Using Fecal Microbiota and Hydrogen Breath Testing

Phase 4

Completed

• Conditions: Irritable Bowel Syndrome
• Interventions: Other: Low FODMAP Diet; Drug: Rifaximin 550 MG

• Registration Number: NCT03219528
• Lead Sponsor: University of Michigan

Brief Summary

Diarrhea-predominant irritable bowel syndrome (IBS-D) is a highly prevalent but poorly understood condition with limited treatment options. Current therapies, including a nonabsorbable antibiotic rifaximin or diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP), show efficacy in 50% or less of patients. In this proposal, we will randomize IBS-D patients to receive either rifaximin or low FODMAP dietary intervention.

Detailed Description

Diarrhea-predominant irritable bowel syndrome (IBS-D) is a highly prevalent but poorly understood condition with limited treatment options. Recent evidence has established small intestinal bacterial overgrowth (SIBO) and alterations in fecal microbiota as potential etiologies in the pathogenesis of IBS-D. Current therapies, including a nonabsorbable antibiotic rifaximin or diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP), show efficacy in 50% or less of patients \[1-4\]. It has been postulated that limited responses to therapies may stem from failure to identify distinct subgroups in IBS-D stratified by gut microbial profiles. In this proposal, we will randomize IBS-D patients to receive either rifaximin or low FODMAP dietary intervention. We will then longitudinally follow the results of fecal microbiota-derived data as well as hydrogen breath tests to define SIBO. We will use these methods to test the hypotheses that: (i) distinct IBS-D phenotypes can be generated by defining fecal microbial populations as well as delineating the presence or absence of SIBO; and (ii) longitudinal analyses using microbe-derived metrics and SIBO status may relate to response to treatment with rifaximin or low FODMAP dietary intervention.

Study Timeline

• Study First Submitted: 2017-07-13
• Study First Submitted QC: 2017-07-13
• Study First Posted: 2017-07-17
• Study Start: 2018-02-13
• Primary Completion: 2024-02-28
• Study Completion: 2024-02-28
• Status Verified: 2024-04
• Last Update Submitted: 2024-04-26
• Last Update Posted: 2024-04-29

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 64

Inclusion Criteria

Adult subjects greater than or equal to 18 years of age who meet Rome IV criteria for diarrhea-predominant irritable bowel syndrome (IBS-D).

Prior colonoscopy or sigmoidoscopy within the past 2 years with random colon biopsies to exclude the presence of microscopic colitis.

IBS medications, including anti-depressants, will be allowed if the dose has been stable for at least 1 month before inclusion. Medications will be carefully tracked to follow any potential confounding issues.

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Exclusion Criteria

Underlying celiac disease, inflammatory bowel disease, or other organic disease that could explain their symptoms.

Subjects with a history of GI tract surgery, except for cholecystectomy or appendectomy, will also be excluded from the study.

Women who are pregnant or breastfeeding Antibiotics taken within 3 months prior to enrollment will not be permitted. Subjects on probiotics must discontinue their use at least 1 month prior to enrollment.

Subjects who have previously received formal dietary education for IBS, including a low FODMAP diet, or previously received antibiotics, including rifaximin, for treatment of IBS-D will be excluded from the study.

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Low FODMAP Group	Low FODMAP Diet	Low FODMAP diet for 4 weeks
Rifaximin	Rifaximin 550 MG	Rifaximin 550 mg three times daily for 14 days

Primary Outcome Measures

Name	Time	Method
Improvement in Mean Daily Pain and/or Bloating	4 weeks	The primary outcome will be changes in mean daily pain or bloating by visual analog scale (VAS) after intervention compared with baseline. Responders to intervention will be defined by ≥ 30% reductions in mean daily pain or bloating by VAS compared with baseline.

Secondary Outcome Measures

Name	Time	Method
IBS Symptom Severity Scale	4 weeks	Secondary outcomes will be defined by reduction in IBS Symptom Severity Scale by ≥ 50 compared with baseline.

Trial Locations

Locations (1)

University of Michigan; 🇺🇸 Ann Arbor, Michigan, United States