Abdominal Pain Severity Is Mainly Associated with Bloating Severity in Patients with Functional Bowel Disorders and Functional Abdominal Pain

Abdominal pain is a cardinal sign of functional bowel disorders (FBD), in favor of irritable bowel syndrome (IBS). However, the determinants of abdominal pain severity (APS) are unknown. The present study aimed to search the relationships between APS and demographic, psychological, and clinical parameters in tertiary care FBD outpatients. In this retrospective study, we included 2043 new outpatients with FBD or functional abdominal pain. They fulfilled the Rome III questionnaire, psychological evaluation, and four 10-points Likert scale for the perceived severity of constipation, diarrhea, bloating, and abdominal pain. Linear regression was performed for each phenotype to model the severity of abdominal pain with demographic, psychological parameters, and symptoms severity. APS was positively associated with bloating severity in all phenotypes, but APS was also associated with other variables according to gender and phenotype. APS was negatively associated with age and positively with depression, constipation severity, and diarrhea severity in female patients. In male patients, APS was associated with state anxiety, constipation severity, and diarrhea severity. APS severity was associated with bloating severity and transit severity in IBS patients, while in non-IBS patients, APS was only associated with bloating severity. Perceived abdominal pain severity is always associated with perceived bloating severity in FBD and FAP patients.