Patterns of alternation in irritable bowel syndrome

BACKGROUND AND AIMS: Irritable bowel syndrome (IBS) is one of the most frequent functional gastrointestinal disorders, having its subtypes related to the predominant bowel pattern: IBS with diarrhea (IBS-D), IBS with constipation (IBS-C), mixed IBS (IBS-M) or alternating IBS (IBS-A). Some patients alternate between subtypes (IBS-A). We looked for the prevalence of alternation between subtypes in patients with IBS. We also analyzed changes in pharmacological therapy specifically addressed to IBS. METHODS: We performed a retrospective observational study that included 60 patients diagnosed with IBS according to Rome III criteria. Patients were asked using a detailed structured interview about their stool form changes regarding previous six months. Alternators were defined as patients that changed IBS subtype over time (previous six months). RESULTS: Out of the 60 patients diagnosed with IBS, 18 patients (30%) were alternators. Of these, 8 patients (44%) changed twice the subtype. Two patients (66.66%) of the IBS-M subgroup shifted between subtypes. Eight patients (44.44%) changed medication over the six months. Four patients (22.2%) of the alternators were on double association of therapy (antispasmodics) addressed to IBS. Four patients (22.22%) discontinued medication. CONCLUSIONS: Patients with IBS often change between subtypes even within six months. Alternators in our pilot study represented 30% of IBS patients. IBS-M seems to be the least stable phenotype. The rarest change is the shift between IBS-C and IBS-D. Alternators also often change their pharmacological treatment (antispasmodics).