Overlap of Rome IV Irritable Bowel Syndrome and Functional Dyspepsia and Effect on Natural History: A Longitudinal Follow-up Study.

ABSTRACT Objectives Disorders of gut-brain interaction, such as irritable bowel syndrome (IBS) and functional dyspepsia (FD) frequently overlap, but the impact of this on the natural history is unknown. We examined this issue in a longitudinal follow-up study conducted in a large cohort of individuals. Methods We collected complete demographic, symptom, mood, and psychological health data from 1374 adults who self-identified as having IBS. We applied the Rome IV criteria to examine what proportion met criteria for IBS and FD, as well as the degree of overlap between them. At 12 months, we collected data regarding IBS symptom severity and impact, consultation behavior, treatments commenced, and psychological health according to degree of overlap between IBS and FD. Results Overall, 807 individuals met the Rome IV criteria for IBS at baseline and provided complete data. At study entry, overlap of FD occurred in 446 (55.3%) people who met Rome IV criteria for IBS. At 12 months, 451 (55.9%) individuals were successfully followed up. The proportion of individuals consulting their primary care physician (p=0.001) or a gastroenterologist (p Conclusions The natural history of people with IBS with overlap FD defined according to Rome IV criteria is more severe than those with IBS alone. This has important implications for future treatment trials in IBS.