International Psychometric Validation Study of the Intestinal Gas Questionnaire (IGQ)

International Psychometric Validation Study of the Intestinal Gas Questionnaire (IGQ)

Objective: To confirm the psychometrics properties of the Intestinal Gas Questionnaire (IGQ) in subjects with Irritable Bowel Syndrome (IBS) diagnosis and General population both complaining of Gas-Related Symptoms (GRS).

IGQ has been developed previously simultaneously in UK English, French and Spanish through qualitative research with subject interviews. The conceptual framework of the IGQ assesses both GRS and their impact on daily life. Similar concepts were identified for both subjects with IBS diagnosis and general population and complaining of gas-related symptoms.

The IGQ consists of a 24-hour recall symptom diary assessing 7 gas-related symptoms (17 items) and a 7-day recall questionnaire which assesses the impact of those symptoms (26 items)

Observational (non-interventional) study with a cross-sectional part for a subset of adult subjects with a single IGQ completion and a longitudinal cross-over part for a subset of subjects with test-retest IGQ completion for validation of electronic version of IGQ.

300 eligible subjects (100 in each of the 3 countries: France, UK & Spain):

• 180 with IBS diagnosis (60% of recruited subjects)
• 120 from General population (40% of recruited subjects)

Inclusion Criteria:

All (subjects with IBS diagnosis and general population):

• Complaining of gas-related symptoms (GRS) of a certain severity level: subjects with IBS diagnosis and general population need to report a score of 4 or greater on at least one symptom on the symptom screening tool
• Cognitive and linguistic capability to complete several self-questionnaires
• BMI > 18.5 and < 30.0 kg/m2
• Agreement of the subject to participate in the study

Subjects with IBS diagnosis:

• IBS diagnosis using Rome III diagnostic criteria for Functional Gastrointestinal Disorders (21)
• IBS severity: IBS-SSS score of 75 to 300

General population:

• Subjects not fulfilling IBS Rome III criteria
• Regular stool frequency (i.e., between 3 and 21 bowel movements per week)

Exclusion criteria

All (subjects with IBS diagnosis and general population):

• Recent (2 last weeks) change in diet or intake of potentially flatulogenic compounds (fiber, lactulose)
• Organic gastrointestinal disease
• Other functional gastrointestinal disorder as defined by Rome III criteria
• Any severe and progressive disease (e.g. depression, cancer, uncontrolled diabetes, rheumatoid arthritis…)
• Any severe psychiatric disorder (e.g. acute episode of schizophrenia or bipolar disorder…)
• Pregnant women
• Being under the direct hierarchy of the investigatorBelonging to the site's staff team

General population:

• Treatment for diarrhea or constipation including lactulose