Splitting irritable bowel syndrome: from original Rome to Rome II criteria

Diagnosis of irritable bowel syndrome (IBS) and other functional bowel disorders (FBD) is based on symptom evaluation. Clinical criteria have changed over time, yielding different proportions of subjects fulfilling diagnostic requirements. According to new diagnostic criteria (Rome II), subjects considered some years ago to have IBS no longer do so. The aim of this article is to evaluate how patients diagnosed as having IBS according to original Rome criteria have been split, and to which clinical diagnosis they belong today.

Two hundred and eleven subjects meeting original Rome IBS diagnostic criteria were studied: 65 also met Rome II criteria while 146 did not. Subjects were extracted from an epidemiological survey, using home-based personal interviews, on 2000 subjects randomly selected as representative of the Spanish population. Clinical complaints, personal well-being, resource utilization, and health-related quality of life (HRQOL) were compared.

Of the subjects meeting original Rome but not Rome II criteria, the present diagnosis should be: 40%"minor" IBS (IBS symptoms of less than 12 wk duration), 37% functional constipation, 12% alternating bowel habit, 7% functional diarrhea, 3% functional abdominal bloating, and 1% unspecified functional bowel disorder (FBD). Thus, 52 subjects (36%) should not be diagnosed with IBS because they really had other FBD, 59 (40%) because of symptoms consistent with IBD diagnosis but not the required duration or frequency, and 35 (24%) because of symptoms consistent with some other FBD diagnosis but not meeting the required duration. Clinical complaints, personal well-being, resource utilization, and HRQOL were more severely affected in IBS than in other FBD as a group, and in "major" rather than in "minor" forms.

Many subjects meeting original Rome criteria for IBS do not meet Rome II criteria: approximately one quarter of subjects do not have sufficient symptom duration or frequency to be diagnosed with IBS and almost half are now considered as having other ("major" or "minor") FBD.