Subtypes of irritable bowel syndrome on Rome III criteria: a multicenter study.

BACKGROUND AND AIM

The aim of this study was to explore the distribution and clinical characteristics of four subtypes of irritable bowel syndrome (IBS) based on Rome III criteria in Chinese.

METHODS

A total of 754 consecutive IBS outpatients from three tertiary hospitals in China were included. Diagnostic criteria were based on Rome II or Rome III.

RESULTS

Among 754 outpatients, 510 (67.6%) patients met the Rome II criteria, 735 (97.5%) patients met the Rome III criteria and 492 (65.3%) patients met both sets of criteria. Among 735 patients who met the Rome III criteria, 66.3% had IBS with diarrhea (IBS-D), 14.7% had IBS with constipation (IBS-C), 4.2% had mixed IBS (IBS-M) and 14.8% had unsubtyped IBS (IBS-U). Most of the IBS-D, IBS-C and IBS-M patients based on the Rome III criteria matched the diarrhea-predominant IBS, constipation-predominant IBS and alternating IBS based on the Rome II criteria, respectively. Among IBS-U patients, 57.0%, 33.3% and 9.7% had constipation-predominant IBS, diarrhea-predominant IBS and alternating IBS, respectively. For IBS-M, the frequencies of bowel movements were stable in 48.4% patients and variable in 51.6% patients. Defecation urgency and straining were most frequent in IBS-M and least frequent in IBS-U patients than other subtypes. About 77.2% of IBS-U patients had abnormal stool frequency (< 3 times/week or > 3 times/day).

CONCLUSION

The Rome III criteria are more sensitive and practical in diagnosing IBS. IBS-D is the most frequent subtype, which is followed by IBS-U, IBS-C and IBS-M. IBS-U is a new subtype, which warrants further studies.