New Rome IV Criteria for Diagnosing Irritable Bowel Syndrome
In May 2016, the Rome Foundation released the new Rome IV criteria for diagnosing irritable bowel syndrome (IBS). The Rome Foundation is an independent not-for-profit organization that provides support for activities designed to create scientific data and educational information to assist in the diagnosis and treatment of functional gastrointestinal disorders. Worldwide, physicians follow this organization’s lead when diagnosing IBS.
These changes come a decade after the Rome III criteria were released at the Digestive Diseases Week (DDW) meeting in 2006. Changes to the wording and subtyping system in Rome IV demonstrate a significant evolution in the medical community’s understanding of how IBS impacts those who are living with it. For reference purposes, the Rome III and Rome IV criteria are presented below.
| Rome III | Rome IV |
A patient might have IBS if they have had recurrent abdominal pain or discomfort* for at least three months, with onset at least six months previously, and if this has been associated with two or more of the following:
*Discomfort means an uncomfortable sensation not described as pain. |
A patient might have IBS if they had recurrent abdominal pain on average at least one day/week in the last three months, associated with two or more of the following criteria:
*Criteria fulfilled for the last three months with symptom onset at least six months prior to diagnosis |
A Comparative Analysis
Comparing Rome III to Rome IV, the first major change is the removal of the term ‘discomfort’ from IBS criteria. By emphasizing outright pain as a distinguishing factor between IBS and functional constipation/functional diarrhea, Rome IV narrows down the diagnostic process considerably. According to the Rome Foundation, functional bowel disorders exist on a scale of degree of pain or the consistency of stool.1 When there is little or no pain, patients might have functional diarrhea or constipation; patients with greater degrees of pain, however, are more likely to have IBS. This is based on evidence that patients often migrate across categories over time.
A second change includes IBS subtypes. The Rome III criteria classification system required doctors to consider an individual’s total number of stools and evaluate them according to the Bristol Stool Form Scale, in order to classify IBS as IBS-C (constipation), IBS-D (diarrhea), IBS-M (mixed), or IBS-U (un-subtyped). However, since IBS patients can have large periods of time with normal stool consistency, under Rome III, many ended up in the IBS-U category, relative to the other groups. Based on this observation, and the results of a Rome Foundation Normative Symptom Study, the Rome IV criteria now relate to the proportion of days with symptomatic stools (i.e., loose/watery and hard/lumpy) only, rather than all stools (including normal ones). As a result, this significantly reduces the number of IBS patients in the IBS-U group.
Going Forward
Along with the new Rome IV diagnostic criteria, the Rome Foundation will be publishing a number of complementary tools to assist medical professionals in using the new system. These include 5 books: The Rome IV Diagnostic Algorithms, The Rome IV Multidimensional Clinical Profile (MDCP), Rome IV for Primary Care and Non GI Clinicians, Rome IV Pediatric Functional GI Disorders, and a book on validated adult and pediatric questionnaires. Together, these materials are meant to provide better background information to physicians and patients working to establish precise diagnoses and find targeted, personalized treatment that works.