2.4. Questionnaires, Tests, and Biological Samples
GI and extra-GI symptoms
At baseline, patients completed the standard Gastroenterology Group Practice symptom and Gastrointestinal Symptom Rating Scale (GSRS) questionnaires to assess demographics, GI and extra-GI symptoms, personal history, and dietary habits [During treatment periods, the tests listed below were performed within 4 weeks after study inclusion and before the first treatment period, before the start of the second treatment period after a minimum washout period of 14 days, and in the 6th week of each treatment period (