Background The validity of Rome III criteria for diagnosing functional gastrointestinal disorders (FGIDs) have been frequently questioned in the literature. In epidemiology, when a disease is diagnosed, the existence of a true cluster must be proven. Thus, clustering the common GI symptoms of individuals and comparing the clusters with FGIDs defined by the Rome III criteria could provide insights about the validity of FGIDs defined by those criteria. Well-separated compact clusters were detected in responses to questionnaires of the epidemiological features of different FGIDs in Iranian adults using fuzzy ordinal clustering. The representative sample from each cluster i.e. Cluster Representative (CR) was formed whose corresponding FGID was diagnosed with Rome III criteria. Then, FGID diagnosis was performed for all participants in each cluster and the percentage of cases whose FGID was the same as the cluster's identified FGID (agreement) was reported. Results Fourteen valid clusters were detected in 4763 people. The average membership of the objects in each cluster was 77.3%, indicating similarity of the objects in clusters to their corresponding CRs. Eight clusters were assigned to single FGIDs (irritable bowel syndromes: constipation IBS-C, diarrhea IBS-D and un-subtyped IBS-U; functional bloating FB; functional constipation FC; belching disorder BD. The agreement was higher than 50% in single FGID clusters except those whose diagnosis was IBS-U. Conclusions IBS-C, IBS-D, FC, BD, and FB defined with Rome III criteria exist in the population, which is not the case for IBS-U.

中文翻译：

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功能性胃肠疾病基于症状的序数尺度模糊聚类

背景技术罗马III标准诊断功能性胃肠疾病（FGID）的有效性在文献中经常受到质疑。在流行病学中，当诊断出疾病时，必须证明存在真正的簇。因此，将个体的常见GI症状进行聚类并将该聚类与Rome III标准定义的FGID进行比较可以提供有关这些标准定义的FGID有效性的见解。使用模糊序数聚类对伊朗成年人中不同FGID的流行病学特征的调查表的响应中检测到分离良好的紧凑型聚类。形成了每个聚类的代表性样本，即聚类代表（CR），其相应的FGID已根据Rome III标准进行了诊断。然后，对每个群集中的所有参与者执行了FGID诊断，并报告了FGID与群集的已识别FGID（协议）相同的病例百分比。结果在4763人中检测到14个有效簇。每个群集中的对象的平均成员资格为77.3％，表明群集中的对象与其对应的CR相似。八个群集被分配给单个FGID（肠易激综合症：便秘IBS-C，腹泻IBS-D和未亚型IBS-U；功能性腹胀FB；功能性便秘FC；气障碍BD。单项一致性高于50％结论除诊断为IBS-U的FGID聚类外，结论人群中存在以Rome III标准定义的IBS-C，IBS-D，FC，BD和FB，IBS-U则并非如此。