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

Phase 4CompletedNCT03219528

University of Michigan74 enrolled

Overview

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, participants with IBS-D will be randomized to receive either rifaximin or low FODMAP dietary intervention.

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, participants with IBS-D will be randomized to receive either rifaximin or low FODMAP dietary intervention. The results of fecal microbiota-derived data as well as hydrogen breath tests will then be longitudinally followed to define SIBO. These methods will be used 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 Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Enrollment

Conditions

Irritable Bowel Syndrome

Interventions

Rifaximin 550 MGDRUG

Rifaximin 550 mg three times daily for 14 days

Low FODMAP DietOTHER

Low FODMAP dietary intervention for 4 weeks

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

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. 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.

Locations (1)

University of Michigan

Ann Arbor, Michigan, United States

Outcomes

Primary Outcomes

Change in Mean Daily Abdominal Pain

Change in mean daily abdominal pain was measured using a visual analog scale (VAS) after intervention compared with baseline. VAS was a scale of 0 to 10, with higher numbers indicating a higher degree of pain; 0 indicated no pain and 10 indicated severe pain.

Time frame: Baseline, Week 5

Change in Mean Daily Bloating

Change in mean daily bloating was measured using a visual analog scale (VAS) after intervention compared with baseline. VAS was a scale of 0 to 10, with higher numbers indicating a higher degree of bloating; 0 indicated no bloating and 10 indicated severe bloating.

Time frame: Baseline, Week 5

Secondary Outcomes

Change in Irritable Bowel Syndrome (IBS) Symptom Severity Scale

The IBS Symptom Severity Scale was comprised of 5 questions each of which was on a scale of 0 to 100, with higher scores indicating more severe symptoms. The total range of the scale was 0 to 500, with 0 meaning no IBS symptoms and 500 indicating severe IBS symptoms.

Time frame: Baseline, Week 5

Change in Gastrointestinal System Ratings Scale (GSRS)

The GSRS was a disease-specific instrument of 15 items combined into five symptom clusters depicting Reflux, Abdominal Pain, Indigestion, Diarrhea, and Constipation. The GSRS had a seven-point graded Likert scale where 1 represents absence of troublesome symptoms and 7 represents very troublesome symptoms. The total range of the scale is 15 to 105 with 15 meaning low symptom burden and 105 meaning high symptom burden.

Time frame: Baseline, Week 5

Change in Stool Form

The Bristol Stool Form Scale was a diagnostic tool used to assess various digestive issues based on the type and shape of stool. The total range of the scale was 1 to 7, with 1 indicating hard stool and 7 indicating liquid stool.

Data from ClinicalTrials.gov

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