Outcome
Type |
Measure |
Description |
Time frame |
Safety issue |
Other |
Visceral Sensitivity and Bacterial Fermentation |
Visceral Sensitivity and Bacterial Fermentation measured by the Lactulose Nutrient Challenge Test. To assess if visceral sensitivity and/or bacterial fermentation are predictors of clinical response to the low FODMAP diet or clinical worsening to the moderate/high FODMAP diet. |
Baseline (day 0) |
|
Other |
Change in microbiota content of frozen fecal samples |
Fecal microbiota analysis using 16 S RNA technique and Dysbiosis Test. Analyses will be done on samples from before and after both dietary periods. |
Baseline (day 0), day 7, day 21, day 28 |
|
Other |
Change in metabolites content |
Frozen urine/serum/fecal samples will be analyzed in the future by gas/liquid chromatography mass spectrometry (metabolomics) analysis.Analyses will be done on samples from before and after both dietary periods. |
Baseline (day 0), day 7, day 21, day 28 |
|
Primary |
Change in Irritable Bowel Syndrome-Severity Scoring System (IBS-SSS) (7-10 days recall questionnaire) |
Irritable Bowel Syndrome-Severity Scoring System (IBS-SSS) is a validated questionnaire that incorporates typical IBS symptoms such as abdominal pain, abdominal distension and bowel dysfunction, as well as quality of life. Subjects rated their symptoms on a visual analogue scale. The maximum achievable score is 500 points (sum of the 5 scales). A reduction in the total IBS-SSS score of at least 50 points is considered to indicate a clinically significant improvement in symptoms. The scale can also be used to classify IBS symptoms severity: <75 points (no symptoms), 75-175 points (mild symptoms), 175-300 points (moderate symptoms) and >300 points (severe symptoms). Measured after both dietary periods and at baseline of both periods. |
Baseline (day 0), day 7, day 21, day 28 |
|
Primary |
Change in Irritable Bowel Syndrome-Severity Scoring System (IBS-SSS) (modified, daily IBS-SSS) |
Irritable Bowel Syndrome-Severity Scoring System (IBS-SSS) is a validated questionnaire that incorporates typical IBS symptoms such as abdominal pain, abdominal distension and bowel dysfunction, as well as quality of life. Subjects rated their symptoms on a visual analogue scale. The maximum achievable score is 500 points (sum of the 5 scales). A reduction in the total IBS-SSS score of at least 50 points is considered to indicate a clinically significant improvement in symptoms. The scale can also be used to classify IBS symptoms severity: <75 points (no symptoms), 75-175 points (mild symptoms), 175-300 points (moderate symptoms) and >300 points (severe symptoms). Measured after both dietary periods and at baseline of both periods. |
Daily during day 7 to 14, and day 21 to 28 |
|
Primary |
Change in Gastrointestinal Symptom Rating Scale - Irritable Bowel Syndrome (GSRS-IBS) |
Change in Gastrointestinal Symptom Rating Scale - Irritable Bowel Syndrome (GSRS-IBS) measures symptom severity and symptom frequency in IBS patients and is a reliable and validated questionnaire. Thirteen questions are evaluated and rated from 1 (no discomfort at all) to 7 (very severe discomfort) on a Likert scale. The total scores can range from 13 to 91 (sum of the domains). The GSRS-IBS evaluates 5 domains: abdominal pain, bloating, constipation, diarrhea and satiety. Measured after both dietary periods and at baseline of both periods. |
Baseline (day 0), day 7, day 21, day 28 |
|
Secondary |
Change in stool consistency and frequency, measured by Bristol Stool Form (BSF) |
Change in Bristol Stool Form, stool consistency/frequency per day after both dietary periods |
Baseline (day 0), day 7, day 21, day 28 |
|
Secondary |
Change in Hospital Anxiety and Depression Scale (HADS) score |
The Hospital Anxiety and Depression Scale (HADS) contains 7 items for depression and 7 for anxiety. Each item is scored from 0 to 3, and therefore the total score per sub-scale can range from 0 to 21. When subjects score >10 on 1 or 2 of the sub-scales, clinically significant psychological distress (anxiety or depression) is likely present. Measured after both dietary periods and at baseline of both periods. |
Baseline (day 0), day 7, day 21, day 28 |
|
Secondary |
Change in Patient health questionnaire-15 (PHQ-15) |
The (PHQ-15) is a validated questionnaire that evaluates 15 somatic symptoms and can be used as a screening tool for somatization in clinical research. The maximum score for men is 28 and 30 for women due to a question about menstrual problems. Measured after both dietary periods and at baseline of both periods. |
Baseline (day 0), day 7, day 21, day 28 |
|
Secondary |
Change in Visceral Sensitivity Index (VSI) |
The Visceral Sensitivity Index (VSI) is a validated and reliable psychometric instrument which assesses gastrointestinal symptom-specific anxiety. The VSI contains 15 items that are scored from 0 to 5, therefore the total score can range from 0 to 75. Higher scores indicate more severe gastrointestinal symptom-specific anxiety. Measured after both dietary periods and at baseline of both periods. |
Baseline (day 0), day 7, day 21, day 28 |
|