About this trial

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.

Eligibility criteria

This trial does not accept healthy volunteers

Qualifiers

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

Disqualifiers

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

Trial design

Design model

Parallel

Treatments tested in this trial

FODMAP Diet
Other intervention
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.
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.

Treatment groups

235 Participants

are divided into 2 treatment groups

Group A: FODMAP DietExperimental treatment 1 intervention

Group B: Exposure-based Cognitive Behavioral Therapy (E-CBT)Experimental treatment 1 intervention

Trial outcomes

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.

Time frame

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

Secondary outcomes

1

Change from baseline in 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.

Time frame

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

2

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

The IBS-SSS is a 5-item measure of the severity of IBS symptoms: frequency and severity of abdominal pain, severity of bloating, dissatisfaction with bowel habits and impact on life in general. Questions ask about IBS and gut symptoms during the past 7 days except question 4 which asks participants to enter the number of days they get pain in every 10. days. A total score ranging from 0 to 500. Mild, moderate and severe cases are indicated by scores of 75 to \<175, 175 to \<300 and \>300 respectively

Time frame

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

3

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

IBS-QOL is used to assess the impact on quality of life for patients with IBS and consists of 34 items scored between 1 and 5, resulting in a maximum score of 170.

Time frame

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

4

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

NIAS is a 9-item measure of ARFID symptoms. The scale has 9 questions, scored from 0 (strongly disagree) to 5 (strongly agree) and summed into three subscales (fear of adverse consequences, lack of interest/appetite, and sensory sensitivity); each range = 0-15), with higher scores indicating greater severity.

Time frame

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

Other outcomes

1

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

The VSI is a 15-item measure of gastrointestinal-specific anxiety, scored on a Likert scale of 1 to 6 with 1=strongly agree; 2=moderately agree; 3=mildly agree; 4=mildly disagree; 5=moderately disagree and 6=strongly disagree. The VSI is being measured as a putative mediator.

Time frame

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.

2

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

IBS-BRQ is a 26-item measure of avoidance behavior. The scale has 26 items, scored from 1 (never) to 7 (always), indicating how persistently the particular avoidance or toilet behavior is carried out. IBS-BRQ is measured as a putative mediator.

Time frame

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.

3

Total FODMAP intake measured using 3-day food diary

Participants will record their food intake for 3 days (including one weekend day) using paper or an app. Total FODMAP intake will be calculated g/day. Total FODMAP intake is being measured as a putative mediator.

Time frame

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.

4

Treatment preference

Baseline treatment preference will be assessed with a single question prior to randomization: "If you had a choice, which treatment would you prefer to receive?". Three response options will be provided: FODMAP diet program; Cognitive Behavioral Therapy program; No preference. Measured as a putative moderator.

Time frame

Baseline (prior to start of intervention) as a putative moderator.

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

About this trial

Eligibility criteria

Qualifiers

Disqualifiers

Trial design

Treatments tested in this trial

Treatment groups

Trial outcomes

Primary outcomes

Secondary outcomes

Other outcomes

Sponsors and contacts