Exclude or Expose in Irritable Bowel Syndrome: What Works for Whom and How?

NCT06940596 | Recruiting DMC

• 3 other identifiers: CT312932024APP2025943
• Study Type: interventional
• Target: 235
• Locations: 1 country
• Sites: 1

Brief Summary

This research project will assess how two treatments for irritable bowel syndrome (one dietary and one behavioral) work and for whom. This will be done by assessing moderators (what treatment works for who and in what context) and mediators (how treatment works). Investigators will also assess how the diet and behavioral treatments affect IBS symptoms during treatment. Participants will be randomized to either: i. A FODMAP diet online program that focuses on modifying the consumption of foods high or moderate in fermentable carbohydrates (FODMAPS) to manage IBS symptoms. or, ii. An Exposure-based Cognitive Behavioral Therapy (E-CBT) online program for IBS that focuses on changing symptom-related behaviors which are known to worsen IBS symptoms.

Conditions

Irritable Bowel Syndrome (IBS); Intestinal Diseases; Gastrointestinal Disease

Keywords

Irritable Bowel Syndrome; FODMAP Diet; Behavior Therapy; Gastrointestinal Diseases; Cognitive Behavioral Therapy; Exposure Based Cognitive Behavioral Therapy; Intestinal Diseases; Digestive System Diseases; Low FODMAP Diet

Outcome Measures

Primary Outcomes (1)

• Gastrointestinal Symptom Rating Scale-Irritable Bowel Syndrome (GSRS-IBS )

  The GSRS-IBS is a 13-item measure of IBS symptom severity to reflect the last 7 days. The items are scored between 1 (no discomfort at all) and 7 (very severe discomfort), rendering a total score between 13 and 91.

  Measured weekly between baseline (prior to intervention) and after intervention completed (week 12).

Secondary Outcomes (26)

• Change from baseline in Gastrointestinal Symptom Rating Scale-Irritable Bowel Syndrome (GSRS-IBS)

  Baseline and 3-and 6 month follow up time points after intervention completed (week 12).

• Change from baseline in Irritable Bowel Syndrome - Symptom Severity Score (IBS-SSS) questionnaire

  Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.

• Change from baseline in IBS quality of life (IBS-QOL) questionnaire

  Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.

• Change from baseline in Nine Item ARFID (Avoidant Restrictive Food Intake Disorder) Screen (NIAS) questionnaire

  Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.

• Change from baseline in Fear of Food Questionnaire (FFQ) questionnaire

  Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.

Other Outcomes (9)

• Gastrointestinal Specific Anxiety (GSA) measured using Visceral Sensitivity Index (VSI)

  VSI will be measured 2nd weekly between baseline (prior to intervention), after intervention (week 12) and and at follow up timepoints of 3-and 6 months following the 12-week intervention as a putative mediator.

• Avoidance behavior measured using Irritable Bowel Syndrome-Behavioural Responses Questionnaire (IBS-BRQ)

  IBS-BRQ will be measured 2nd weekly between baseline (prior to intervention), after intervention (week 12) and and at follow up timepoints of 3-and 6 months following the 12-week intervention as a putative mediator.

• Total FODMAP intake measured using 3-day food diary

  Total FODMAP intake will be measured 2nd weekly between baseline (prior to intervention), after intervention (week 12) and and at follow up timepoints of 3-and 6 months following the 12-week intervention as a putative mediator.

Study Arms (2)

FODMAP Diet

EXPERIMENTAL

Fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) Diet is a 12-week online intervention with dietitian support.

Other: FODMAP Diet

Exposure-based Cognitive Behavioral Therapy (E-CBT)

EXPERIMENTAL

Exposure-based Cognitive Behavioral Therapy is a 12-week online intervention with psychologist support.

Behavioral: Exposure-based Cognitive Behavioral Therapy

Interventions

FODMAP Diet OTHER

The intervention is an online diet program. The diet is the low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet. It is a 3-phase diet which involves: 1.Phase 1 FODMAP restriction: restrict foods high or moderate in FODMAPs and swap these for low FODMAP alternatives; 2. Phase 2 FODMAP reintroduction: continue to follow a low FODMAP diet and complete a series of food challenges to understand which foods and FODMAPs are tolerated and which trigger symptoms; 3. Phase 3 FODMAP personalization: include well-tolerated foods and FODMAPs back into the diet, and restrict poorly tolerated foods and FODMAPs to a level needed to maintain symptom relief. The online FODMAP program is a self-directed diet program with support from an online clinician (Accredited Practicing Dietitian \[APD\]). The content is delivered over 12 weeks. After each module participants will complete homework activities and questions and submit them to the dietitian for feedback.

FODMAP Diet

Exposure-based Cognitive Behavioral Therapy BEHAVIORAL

The intervention is an online behavioral therapy program. The behavioral therapy is Exposure-based Cognitive Behavioral Therapy (E-CBT) Program. The E-CBT program is organised into six steps to be completed over 12 weekly modules with support from an online clinician (Psychologist). The first step contains a rationale for the treatment and instructions on self-observation. Steps 2, 3 and 4 contain a presentation of a psychological model of IBS and continued self-observation exercises. The fifth step covers exposure exercises, divided into three categories; (1) exercises that provoke symptoms, (2) abolishment of behaviors that serve to control symptoms, (3) exposure to situations where symptoms were unwanted. The final step (Step 6) includes how to handle relapses into avoidance behaviors and how to maintain a widened behavioral repertoire. After each module participants will be directed to complete homework activities and questions and submit them to the psychologist for feedback.

Exposure-based Cognitive Behavioral Therapy (E-CBT)

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Living in Australia or the United States
• Aged 18 years or older
• Body Mass Index (BMI) \[Equation\]18.5kg/m2 and \[Equation\] 34.9kg/m2
• Diagnosed with IBS by a General Practitioner, Family Physician, or Gastroenterologist, or Advanced Specialist Dietitian
• Currently fulfill Rome IV criteria for IBS
• Symptomatic at the time of recruitment (IBS-SSS \> 175)
• Access to a computer and internet
• Sufficient English language and computer skills to complete a text-based online treatment
• Willing to make dietary or behavioral changes in line with the allocated treatment program
• Ability to provide informed consent

You may not qualify if:

• Presence or known history of other GI disease (e.g. coeliac disease, Inflammatory Bowel Disease) or history of gastrointestinal cancer
• History of major gastrointestinal surgery (not appendectomy, cholecystectomy or hemorrhoidectomy)
• Individuals who report alarm symptoms (e.g., blood in stool, recent unexplained/unintentional weight loss \>5% body weight, a recent change in bowel habits if \>50 years, family history of gastrointestinal cancer or gastrointestinal diseases, large volumes of diarrhea occurring at night, fever associated with gut symptoms, recurrent vomiting, persistent unexplained iron deficiency) will be excluded if appropriate medical investigations have not been conducted, unless written medical approval is provided from a general practitioner, family physical, or gastroenterologist.
• Diagnosis of major disease that could explain current gastrointestinal symptoms such as severe diabetic, cardiac, liver, neurological, neuropathy disease
• History or current diagnosis of psychotic disorder or bipolar disorder
• Current diagnosis of substance abuse disorder or major depressive disorder or active suicidal ideation
• History or current diagnosis of an eating disorder
• Current enteral/parenteral feeding or use of supplemental feeds (e.g. Ensure)
• Pregnant or lactating or planning to become pregnant during the 12-week intervention period
• Commenced or change in dose of antibiotics and medications that potentially affect the gastrointestinal transit (e.g. anti-diarrheals and laxatives) in the 3 months preceding study commencement.
• Commenced taking or changed dose of probiotics, prebiotics, fibre supplements and digestive enzymes in the 3 months preceding study commencement
• Commenced or change dose in psychotropic medication in the 3 months preceding study commencement
• Are currently undertaking behavioral therapy for IBS (including cognitive behavioral therapy, CBT), or have undertaken clinician-delivered behavioral therapy for the treatment of IBS
• Are currently undertaking or have undertaken a dietitian-prescribed and delivered restrictive diet for IBS (e.g., FODMAP diet).

Sponsors & Collaborators

• University of Melbourne: lead
• Monash University: collaborator

Study Sites (1)

University of Melbourne

Melbourne, Victoria, 3010, Australia

RECRUITING

Related Publications (1)

• Biesiekierski JR, Manning LP, Murray HB, Vlaeyen JWS, Ljotsson B, Van Oudenhove L. Review article: exclude or expose? The paradox of conceptually opposite treatments for irritable bowel syndrome. Aliment Pharmacol Ther. 2022 Aug;56(4):592-605. doi: 10.1111/apt.17111. Epub 2022 Jul 1.

  PMID: 35775328 BACKGROUND

MeSH Terms

Conditions

Irritable Bowel Syndrome; Intestinal Diseases; Gastrointestinal Diseases; Digestive System Diseases

Interventions

FODMAP Diet

Condition Hierarchy (Ancestors)

Colonic Diseases, Functional; Colonic Diseases

Intervention Hierarchy (Ancestors)

Elimination Diets; Diet; Nutritional Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena

Study Officials

• Associate Professor Jessica Biesiekierski

  University of Melbourne

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Jessica Biesiekierski, A/Prof

CONTACT

+61 499 272 673; jessica.biesiekierski@unimelb.edu.au

Jacqueline L Anderson, APD

CONTACT

jacquia@student.unimelb.edu.au

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: The people analyzing the results/data will be masked
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Participants will be randomized to one of two treatment arms. The randomization schedule will be generated using http://www.randomization.com. Participants will be stratified by site (Australia or US) before randomization.

Study Record Dates

• First Submitted: March 31, 2025
• First Posted: April 23, 2025
• Study Start: May 22, 2025
• Primary Completion (Estimated): October 1, 2027
• Study Completion (Estimated): April 1, 2028
• Last Updated: May 6, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, CSR, ANALYTIC CODE
• Time Frame: The IPD and supporting information will be available beginning 3 months following analysis and article publication for 15 years.
• Access Criteria: The IPD and supporting information will be made available for use by future researchers from a recognized research institution whose proposed use of the data has been ethically reviewed and approved by an independent committee and who accept University of Melbourne conditions for access.

Locations

AU (1)