Online Low-FODMAP Diet in Irritable Bowel Syndrome

The primary outcome was the change in QoL from baseline to the end of study, assessed by the validated IBS-QoL questionnaire. This questionnaire assesses 8 domains, namely dysphoria, interference with activity, body image, health worry, food avoidance, social reaction, sexual concerns and relationships, from which a computed score is drawn. This score, ranging from 0 to 100, was developed to assess the self-reported QoL in IBS, a higher score indicating a better QoL.

Secondary outcomes included changes in severity of IBS symptoms, measured by the validated IBS-Severity Scoring System (IBS-SSS). This questionnaire evaluates 5 specific domains within the last ten days: abdominal pain severity, abdominal pain duration, abdominal distension, bowel habits dissatisfaction and interference with life. A composite score is calculated and varies from 0 to 500. Depending on the score, the severity can be classified in 4 categories: absence of symptoms severity or remission (score < 75), mild (score 75-174), moderate (score 175-299), and severe (score ≥ 300).

Anxiety was evaluated by the French-Canadian adaptation of the State-Trait Anxiety Inventory Form Y (STAI), which specifically assesses state anxiety (STAI-S), the subjective and transient emotional state of anxiety, and trait anxiety (STAI-T), a more stable predisposition to anxiety. The STAI-S score can be classified in 5 categories: very low state anxiety (score < 36), low (score 36-45), moderate (score 46-55), high (score 56-65), and very high (score > 65). For the STAI-T score, a score inferior to 40 commonly indicates low trait anxiety while a score of 40 or more indicates high trait anxiety.