Factor Analysis Defines Distinct Upper and Lower Gastrointestinal Symptom Groups Compatible With Rome IV Criteria in a Population-based Study

Background & Aims: The Rome IV criteria define functional gastrointestinal (GI) disorders by specific combinations of symptoms. It is possible to empirically evaluate these symptom combinations by factor analysis (a statistical procedure that groups variables that correlate). However, this analysis has not been performed for the Rome IV criteria, and factor analyses based on the previous versions of the Rome criteria did not use population-based data. We therefore investigated symptom grouping by the Rome IV questionnaire using factor analysis of a population-based sample. Methods: The Rome IV questionnaire was completed online in English by 5931 respondents from the United Kingdom, United States, and Canada (49% female, age range, 18–92 years). We performed an exploratory factor analysis on the Rome IV questions. Next, we performed a confirmatory factor analysis to compare the exploratory factor result to that of the Rome IV criteria. Results: The exploratory factor analysis identified 8 factors that accounted for 45% of the variance in response: constipation, diarrhea, irritable bowel syndrome, abdominal pain, heartburn, nausea or vomiting, globus, and other upper GI symptoms. Most factors corresponded to distinct functional GI disorders defined by the Rome IV criteria—exceptions included abdominal pain and upper GI symptoms. In confirmatory factor analysis, the exploratory model fitted slightly better than that based on the Rome IV criteria (root mean square error of approximation, 0.063 vs 0.077). Conclusions: We used factor analysis to identify distinct upper and lower GI symptom groups that are compatible with the Rome IV criteria. Our findings support the use of the Rome IV criteria in research and clinical practice as a basis for development of diagnostics and management of patients.