The overlap of upper functional gastrointestinal disorders with irritable bowel syndrome in Chinese outpatients: A multicenter study

Background and aim Irritable bowel syndrome (IBS) is a common functional bowel disease, and the overlap with upper functional gastrointestinal disorders (FGIDs) is popular. However, the coexistent upper GI symptom profiles, upper FGID spectra, and related risk factors among IBS subjects remain unclear in mainland of China. Methods Consecutive patients from the outpatient gastroenterology clinics of three tertiary hospitals in China were enrolled in this multicenter study. All upper GI symptoms occurring at least once a week in the last 3 months were recorded. Diagnostic criteria of functional esophageal, gastroduodenal disorders and IBS were based on Rome III criteria. Risk factors were assessed using a multivariate logistic regression model. Results Of the 8906 consecutive patients, 751 patients met Rome III criteria for IBS and 735 IBS patients participated in the interview. Postprandial fullness (30.6%), belching (27.1%), and regurgitation (21.8%) were the three most prevalent upper GI symptoms in IBS. Functional dyspepsia (FD, 36.7%), belching disorders (27.1%), and functional heartburn (16.3%) were the three most frequent upper FGID in IBS patients. Female sex, divorced or widowed versus married status, defecation straining, reduced bowel movement, mixed IBS, abdominal distention, mild abdominal pain, moderate discomfort were positively associated with IBS-FD overlap. Female sex, drinking, moderate discomfort, and mild to moderate distension were independent risk factors for IBS-belching disorder overlap. Conclusions The study provides detailed overlap spectra of upper FGID with IBS. Mixed IBS is an important risk factor for IBS-FD overlap, which deserved more concern.