M1349 ROME II Versus ROME III; Impact on Subtyping and Prevalence of Psychiatric Co-Morbidity in Irritable Bowel Syndrome (IBS)

Background: The Rome II criteria sub-typed IBS on the basis of reported symptoms, Rome III uses stool consistency. Considerable data exist on various aspects of IBS, as defined by Rome II; less is known of the impact of Rome III. Aim: To determine the level of agreement between Rome II and Rome III in defining IBS subtypes and to compare psychological comorbidity amongst subtypes so defined. Methods: 160 subjects with a functional GI disorder were recruited from a specialty clinic. Each completed the Rome III diagnostic questionnaire, an abridged version of the Rome II modular questionnaire and the patient health questionnaire. IBS was defined and subclassified by Rome III criteria as IBS with constipation (IBSC), IBS with diarrhea (IBS -D), mixed IBS (IBS-M) and unsubtyped IBS (IBS-U) and by Rome II as constipation predominant IBS (CP -IBS), diarrhea predominant IBS (DP-IBS) and alternating IBS (A- IBS). Co-morbid psychiatric conditions were defined by the patient health questionnaire. Results: 118/160 subjects fulfilled Rome III criteria for diagnosis of IBS. In terms of subtyping, the overall agreement between Rome II and Rome III criteria was 80/118 (68%); discrepancies were greatest for IBS-M (Table 1). Somatoform disorder was present in 72 (61%), a depressive disorder in 34 (29%), an anxiety disorder in 11 (9%), a panic disorder in 12 (10%) and an eating disorder in 5 (4%). Psychiatric co-morbidity was least common among C-IBS subjects and most prevalent among those with M-IBS (Table 2). The prevalence of co-morbidity was unaffected by whether Rome II or III criteria were used to define subtypes. Conclusions: The major discrepancies between Rome II and Rome III in subtyping IBS relate to IBS-M and IBS-D with 40% of Rome II DP-IBS reclassified as IBS-M. Psychiatric co-morbidity was most common among IBS-M; its prevalence was unaffected by the subtyping criterion used (Table presented).