Irritable Bowel Syndrome Subtypes Defined by Rome II and Rome III Criteria are Similar

BACKGROUNDThe implications of the Rome III recommendations to change the irritable bowel syndrome (IBS) subtype criteria for stool pattern are unknown. AIM(1) Determine the level of agreement between Rome II and Rome III subtypes and (2) compare the behaviors of Rome II and Rome III subtypes over time. METHODSFemale patients (n=148) with Rome II defined IBS were prospectively tracked over 5 consecutive 3-month periods. At baseline, bowel habit reports on questionnaires were used to subclassify patients into Rome II and Rome III subtypes. Over the subsequent 15 months, bowel habit reports on diary cards were used to subclassify patients based on previously derived surrogate criteria into Rome II and Rome III IBS subtypes. RESULTSThe level of agreement between Rome II and Rome III subtype assignments was quite high (86.5%; κ 0.79). The behavior of Rome II and Rome III subtypes over time was also similar in terms of subtype prevalence, subtype stability, and the proportion of subjects who met criteria for alternating irritable bowel syndrome. CONCLUSIONSRome II and Rome III IBS subtypes are in high agreement and behave similarly over time. Therefore, studies that used Rome II subtype criteria and studies that will use Rome III criteria will define comparable populations.