A Study Comparing the Effectiveness and Convenience of Dietary Therapy for Irritable Bowel Syndrome (IBS)

Study Overview
=================
Brief Summary
-----------------
Irritable bowel syndrome is a functional lower gastrointestinal disorder characterised by abdominal pain and altered bowel habit in the absence of organic pathology to explain the symptoms. Irritable bowel syndrome has a prevalence of approximately 10% in adults, shows a female preponderance, and is more common in younger individuals. In clinical practice, Irritable bowel syndrome accounts for almost a third of all gastroenterology cases seen in primary care, with a subsequent third of these being referred onto secondary-care for further evaluation. The economic burden of Irritable bowel syndrome, in terms of medical expense, work absenteeism and loss of productivity, is considerable. The exact cause of irritable bowel syndrome is unknown. Accordingly there has been a huge surge in interest for dietary therapies to help manage Irritable bowel syndrome. To date, there are only a handful of small randomized controlled trials evaluating the efficacy of dietary therapy in Irritable bowel syndrome. In light of this we plan to conduct the first randomized controlled trial directly comparing the effectiveness of the low-FODMAP diet, British Dietetic Association diet, and the gluten free diet in Irritable bowel syndrome. Moreover, such a trial allows for a direct comparison of nutritional and gut microbial changes, both of which can suffer detrimental consequences following the implementation of restrictive dietary therapies. This study is also unique in that it takes into consideration the patients' perspective with regards to the convenience and cost-effectiveness of implementing such diets into routine day-to-day life. The study will aim to recruit 100 patients from Sheffield Teaching Hospitals gastrointestinal clinics. Following recruitment patients will be seen by a hospital dietitian where they will be randomized to one of the 3 diets. Participants will complete a questionnaire portfolio weekly for one month as part of the study

Official Title
-----------------
E-C DIBS: Randomised Controlled Study: Comparing the Effectiveness and Convenience of Dietary Therapy for Irritable Bowel Syndrome (IBS)

Conditions
-----------------
Irritable Bowel Syndrome

Intervention / Treatment
-----------------
* Other: dietary therapy


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Irritable Bowel syndrome - as defined by abdominal pain and altered bowel habit in the absence of organic pathology to explain the symptoms.This is the contemporary definition as provided by the Rome IV committee. Age 18-65 years English literate Can travel to hospital Telephone/internet access Exclusion Criteria: Inflammatory bowel disease Coeliac disease Gastrointestinal cancer Previous abdominal surgery Scleroderma Poorly controlled diabetes Severe liver disease Severe renal disease Severe respiratory disease Severe cardiac disease Severe psychiatric disease Memory disorders Pregnant Current dietary interventions Recent/current use of Probiotics Recent/current use of Antibiotics Recent/current use of Narcotics Currently titrated antidepressants (i.e. not on a stable dose)

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Low FODMAP diet<br>As part of their treatment for IBS participants may be randomised to a low FODMAP diet | Other: dietary therapy<br>* participants will undertake a four week diet as part of their IBS treatment<br>|
| Active Comparator: Gluten Free Diet<br>As part of their treatment for IBS participants may be randomised to a gluten free diet | Other: dietary therapy<br>* participants will undertake a four week diet as part of their IBS treatment<br>|
| Active Comparator: British Dietetic Association diet<br>As part of their treatment for IBS participants may be randomised to the BDA diet | Other: dietary therapy<br>* participants will undertake a four week diet as part of their IBS treatment<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage with at least 50-point reduction in Irritable bowel syndrome Severity Scoring System questionnaire | A validated questionnaire to assess IBS symptoms and severity. The ranges of this questionnaire are included below: How severe was your pain? 0 (no pain) -100 (very severe) how severe is your abdominal (tummy) pain? 0 (no pain) - 100 (very severe) how severe is your abdominal distention/tightness? 0 (no pain) - 100 (very severe) How satisfied are you with your bowel habit? 0 (very happy) - 100 (very unhappy) Please indicate with a cross on the line below how much your irritable bowel syndrome is affecting or interfering with your life in general. 0 (not at all) - 100 (completely) A higher score on any scale represents a negative outcome. A ≥ 50-point reduction in IBS-SSS following intervention represents a clinically significant improvement | Baseline to week 4 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in proportion with anxiety and depression | Hospital Anxiety and Depression Scale - is a psychological screening tool to which there are in total 14 items, seven each for depression and anxiety. Each item is rated from 0 (not present) to 3 (maximum), giving a cumulative score for each subscale to range from 0 to 21. A subscale score of ≥11 is used to indicate a clinically significant level of anxiety or depression. | Baseline to week 4 | 
| Changes in somatization | The patient health questionnaire (PHQ)-12 non-GI somatic symptoms scale- The PHQ-12 records bothersome non-GI symptoms over the past month. The twelve symptoms assessed are back pain, limb pain, headaches, chest pain, dizziness, fainting spells, palpitations, breathlessness, menstrual cramps, dyspareunia, insomnia, and lethargy. Subjects were asked to rate how much they had been troubled by these 12 symptoms over the last four weeks as 0 (not bothered at all), 1 (bothered a little), or 2 (bothered a lot). Responses were used to calculate the number of sites reporting somatic symptoms (ranging from 0 to 12) and the somatisation severity score (ranging from 0 to 24), which was categorised as minimal (less than or equal to 3), low (4-7), medium (8-12) and high (≥ 13). | Baseline to week 4 | 
| Changes in IBS-quality of life | The IBS quality of life (IBS-QOL) questionnaire - this consists of 34 questions which are summed and averaged for a total score, in addition to eight subscale scores (Dysphoria, Interference with Activity, Body Image, Health Worries, Food Avoidance, Social Reaction, Sexuality, Social Relationship). Total and subscale scores are transformed to a 0-100 scale. Higher scores indicate better IBS-specific QOL. | Baseline to week 4 | 
| Acceptability of dietary restriction | The acceptability of dietary restriction questionnaire is based on the adapted nutrition related quality of life (QOL) questionnaire. Responses are recorded using a Likert scale, with the responses of agree, neutral and disagree. | Week 4 | 
| Food related quality of life (QOL) questionnaire | The food related QOL questionnaire is a seven-item questionnaire based on the food-related QOL tool (Satisfaction with Food-related Life). Responses are recorded on Likert scale, as either agree, neutral and disagree. | Week 4 | 
| Comprehensive Nutrition Assessment Questionnaire | The Comprehensive Nutrition Assessment Questionnaire is a semi-quantitative food frequency questionnaire, consisting of 297 questions, assessing macronutrient and micronutrient intake, as well as FODMAPs, fibre, starch, glycaemic index and glycaemic load | Baseline to week 4 | 
| Changes in stool dysbiosis index | Participants will provide a stool sample both pre- and post-dietary intervention. Data will be analysed by using the GA-map™ Dysbiosis Test (Genetic Analysis AS, Oslo, Norway). Bacterial profiles will be assigned a dysbiosis index (DI), on a scale from 0 to 5, with a DI score of 2 or lower being classified as being within the non dysbiotic region compared to the normobiotic reference range. A DI score of greater than 2 will be considered to be dysbiotic, with a higher DI number indicating greater dysbiosis from the reference range. | Baseline to week 4 |