Colonic transit time and IBS symptoms: what's the link?

The relevance of colonic transit alterations for the overall symptom pattern in irritable bowel syndrome (IBS) is incompletely understood. The aim of this study was to assess the total and segmental colonic transit time (CTT) and their relationship to symptoms and subgroups in a large sample of IBS patients.

Total and segmental CTT was assessed using radiopaque markers in 359 patients with IBS (279 females). These results were compared with existing normal values for healthy men and women without gastrointestinal (GI) symptoms. Stool frequency and consistency (Bristol Stool Form (BSF) scale), and the perceived severity of three GI symptoms (bloating, flatulence, and abdominal pain) were noted in a daily diary during the measurement week. Patients could be classified by the BSF scale characteristics into Rome III subtypes (n=338), or by use of the Rome II modular questionnaire into Rome II subtypes (n=143).

CTT was normal in 287 patients (80%), whereas 53 (15%) had accelerated and 19 (5%) had delayed CTT. Transit abnormalities in relation to gender-specific reference values were more common in males (30.0%) than in females (17.2%; P < 0.05). IBS subgrouping according to Rome III (P < 0.0001) and Rome II criteria (P < 0.001) was associated with the presence of abnormal CTT. Stool form (r=-0.40; P < 0.0001) and stool frequency (r=-0.30; P<0.0001) were moderately and negatively correlated to total CTT. No correlations of clinical significance were found between transit data and the three GI symptoms.

Total and segmental colonic transit alterations are of importance for the abnormal bowel habit seen in men and women with IBS, but of no or minor importance for other IBS symptoms.