An examination of subgroup classification in irritable bowel syndrome patients over time: A prospective study

Background: Irritable bowel syndrome (IBS) is a complex functional gastrointestinal disorder which to date remains poorly understood. Therapies for irritable bowel syndrome (IBS) patients are usually aimed at relieving the predominant symptom; however, little evidence exists as to whether or not the predominant symptom changes with time. Nurses are becoming increasingly involved in the assessment and management of IBS patients. Objectives: To categorise IBS patients into one of three sub-types, namely diarrhoea-predominant, constipation-predominant and a third group who alternate between the two, and to investigate changes in patient sub-type classification over time. Design: Observational cohort study. Setting: The general population of the United Kingdom (UK). Methods: A cohort of 494 IBS patients, with a confirmed Rome II classification diagnosis, was recruited in the UK. Patients' IBS symptoms were recorded throughout a 26-week period. Proportions of individuals in each IBS subgroup were calculated and probabilities of moving from one subgroup to another between consecutive weeks were estimated. Results: The percentage of patients given an overall subgroup classification of diarrhoea-predominant IBD (D-IBS) is 40.9%; 58.1% and 1% were classified as belonging to the alternator (A-IBS) and constipation-predominant (C-IBS) subgroups, respectively. Patients: classified as an alternator or as diarrhoea-predominant have a high probability (0.67 and 0.71, respectively) of remaining in the same subgroup; however this probability is lower for constipation-predominant patients (0.35). Conclusion: Although many patients remain in the same IBS subgroup classification over time, there are individuals whose subgroup classification varies. As such, patients' IBS subgroup classification should be reviewed regularly and treatment adjusted accordingly in order to optimise patient care. © 2008 Elsevier Ltd. All rights reserved.