A Comparison of Three Different Treatment Options for Irritable Bowel Syndrome

The Role of CARbohydrates in Irritable Bowel Syndrome (CARIBS): Protocol for a Randomized Controlled Trial Comparing Three Different Treatment Options

Irritable Bowel Syndrome is a common disease to which there is no curable treatment. Diet is considered to trigger symptoms associated with the clinical picture of IBS, and dietary treatment is thus believed to relieve the symptoms of IBS. As the disease is very heterogeneous in its manifestation, different treatment options might be indicated depending on the predominant symptom. To investigate the response to different dietary treatment options, a randomized controlled intervention trial will be carried out in adult patients (>18 y) with IBS according to Rome IV criteria. The aim of this study is to compare the response to two different dietary treatments or optimized medical treatment.

The study is a randomized controlled trial comparing three different treatments during four weeks:

1. Combination of low FODMAP diet + traditional dietary advice (based on NICE recommendations)

   • Eat at regular hours; 3 main meals and 3 snacks
   • Eat in peace, chew the food properly
   • Peel all fruits and vegetables
   • Limit intake of spicy and fatty foods, coffe, alcohol, avoid fizzy drinks and chewing gum
   • Choose soluble rather than insoluble fibres
   • Avoid foods high in FODMAPs

2. Diet low in carbohydrates

   • 10 E% carbohydrates, 23 E% protein, 67 E% fat
   • Larger amounts of fish, shellfish, meat, egg, dairy products (lactose free if wanted) nuts, seeds, oil, vegetables
   • No sugary or starchy foods, e.g pasta, potatoes, bread, rice, most fruits
   • No specific consideration about FODMAP content

3. Optimized pharmacological tretament based on predominant symptom and previous experience with pharmacological treatmment.

Pain/discomfort:

• Pain: Amitriptyline 25 mg. Increase to 50 mg if needed
• Episodic pain: Hyoscyamine 0,2mg 2x2; adjust dose if needed
• Pain with diarrhea: Amitriptyline 25 mg. Increase dose if needed
• Pain with constipation: Linaclotide 290 microgram 1x1

Constipation:

• Bulking agent (Sterculia gum (Inolaxol) 1x1. Increase to 1x3 if needed
• Osmotic laxative (Macrogol (Movicol) 1x1
• Linaclotide 290 microgram 1x1 Diarrhea
• Loperamide 1x2 . Adjust dose if needed
• Cholestyramine 1x1. Increase ever 3-5 d as needed
• Ondansetron 4mg 1x1. Increase to 1x2-3 if needed
• Eluxadoline 100mg 1x2

Primary endpoint: IBS-SSS reduction >50 points

Inclusion Criteria:

• IBS according to ROME IV criteria, BMI 18-35, ability to communicate in Swedish, Gothenburg region resident

Exclusion Criteria:

• Heart, liver, neurologic or psychiatric disease or illness
• Serious gastrointestinal diseases
• Celiac disease
• Diabetes
• Other conditions or surgery that affects the gastrointestinal function
• Hyperlipidemia
• Food allergy or intolerance other than lactose
• Adherence to a specific diet
• Being pregnant or breastfeeding
• Previously been treated with any of the intervention arms, including having tested all of the pharmacological treatment options of relevance for the symptom profile of the patient