Rome III criteria for functional gastrointestinal disorders: too much overlap to be useful?

Introduction Functional gastrointestinal (GI) symptoms are common. The Rome III classification of these symptoms into mutually exclusive disorders attempts to improve the homogeneity of patients recruited into clinical trials from secondary and tertiary care. Previous investigators have reported significant degrees of overlap between some of these conditions, but no study has examined this issue in its entirety. Methods This was a cross-sectional survey of consecutive new patients consulting a Gastroenterologist at two tertiary care centres. All individuals were provided with the self-administered, validated, Rome III diagnostic questionnaire for the adult functional GI disorders. We scored completed questionnaires according to the algorithm devised by the authors, but suspended the mutual exclusivity between various syndromes, such as dyspepsia, irritable bowel syndrome and functional constipation, required by the questionnaire in order to examine the degree of overlap between them. Results A total of 1822 patients completed the questionnaire. There were 1253 (68.8%) who met criteria for at least one of the functional GI disorders and 880 (70.2%) of these patients met criteria for more than one disorder when the mutual exclusivity was suspended. The degree of overlap between the various disorders varied between 3% and 86% and was greatest for functional vomiting and chronic idiopathic nausea (table 1). Table 1 OC-051 Overlap of Rome III functional GI disorders Rome III functional disorder Postprandial distress syndrome (%) Chronic idiopathic nausea (%) Functional vomiting (%) Irritable bowel syndrome (%) Postprandial distress syndrome (n = 561) 251 (44.7) 65 (11.6) 249 (44.4) Chronic idiopathic nausea (n = 370) 251 (67.8) 77 (20.8) 188 (50.1) Functional vomiting (n = 90) 65 (72.2) 77 (85.6) 39 (43.3) Irritable bowel syndrome (n = 444) 249 (56.1) 188 (42.3) 39 (8.8) Conclusion The degree of overlap between the various Rome III diagnostic was variable but large in some cases. The magnitude of this overlap was of remarkably similar magnitude in some instances. These data suggest that some of these disorders have similar aetiologies or pathogenetic mechanisms and that attempts to classify them separately may be both artificial and futile.