title: Subtypes of irritable bowel syndrome on Rome III criteria: a multicenter study.
abstract: OBJECTIVE
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Gastroenterology and Hepatology, Chinese PLA General Hospital, Beijing, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Yao
authors.forename: Yun Sheng
authors.initials: YS
authors.lastname: Yang
authors.forename: Li Hong
authors.initials: LH
authors.lastname: Cui
authors.forename: Ka Bing
authors.initials: KB
authors.lastname: Zhao
authors.forename: Zhen Hua
authors.initials: ZH
authors.lastname: Zhang
authors.forename: Li Hua
authors.initials: LH
authors.lastname: Peng
authors.forename: Xu
authors.initials: X
authors.lastname: Guo
authors.forename: Gang
authors.initials: G
authors.lastname: Sun
authors.forename: Jun
authors.initials: J
authors.lastname: Shang
authors.forename: Wei Feng
authors.initials: WF
authors.lastname: Wang
authors.forename: Jia
authors.initials: J
authors.lastname: Feng
authors.forename: Qiyang
authors.initials: Q
authors.lastname: Huang
mesh_terms: D015746:Abdominal Pain / Q000209:etiology; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D002681:China; D015331:Cohort Studies; D003248:Constipation / Q000209:etiology*; D003672:Defecation; D003967:Diarrhea / Q000209:etiology*; D005221:Fatigue / Q000209:etiology; D005260:Female; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000145:classification* / Q000150:complications / Q000175:diagnosis*; D008297:Male; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires