Vork L, et al. – This large cohort study aims to ascertain the percentage of Rome III irritable bowel syndrome (IBS) subjects that fulfill Rome IV criteria and to assess differences between Rome IV–positive and Rome IV–negative subjects. The authors reveal that the Rome IV IBS population likely indicates a subgroup of Rome III IBS patients with more severe gastrointestinal (GI) symptomatology, psychological comorbidities, and lower quality of life. This suggests that outcomes from Rome III IBS studies may not be directly comparable to those from Rome IV IBS populations.