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The Rome Foundation criteria for functional gastrointestinal disorders (FGIDs) have traditionally formed the backbone of classification and diagnosis of a wide range of these disorders, including irritable bowel syndrome (IBS).¹ Ten years after its previous update, in 2006, the Foundation released the Rome IV criteria, in May 2016, which included several changes to IBS definitions that potentially will alter the disorder鈥檚 diagnosis in clinical practice. Perhaps most significantly, the diagnostic criteria have changed.

鈥淚n the adult criteria, IBS used to be diagnosed based on the presence of abdominal pain or discomfort at least 3 times a month. The new criteria require that there be pain鈥攕o discomfort doesn鈥檛 qualify鈥攁nd it requires that it occur at least once a week on average,鈥� explains William E. Whitehead, PhD, a professor of medicine in the Division of Gastroenterology and Hepatology and director of the University of North Carolina (UNC) Center for Functional GI and Motility Disorders, in Chapel Hill. Dr. Whitehead has served on the Rome Foundation board since its inception almost 30 years ago; the first IBS guidelines were published in 1989.²

Actually, what is IBS?

IBS is the most commonly recognized such disorder worldwide. Over the years, the concept and definition of IBS has evolved, from being considered an entity separate from other disorders to one that overlaps with them, and, in the Rome IV criteria, to existing on a continuum with functional diarrhea, functional constipation, bloating and distention, and pain. In this conception, IBS occurs at a point associated with more pain than the other components, and can (as before) be predominantly associated with constipation or diarrhea.² 

Rome IV criteria also update the diagnosis of IBS. Principal changes include the elimination of the term 鈥渄iscomfort鈥� from the definition (previously, discomfort and abdominal pain), and the inclusion of abdominal pain present at least 1 day per week during the previous 3 months (previously, at least 3 days a month). The definition further stipulates that pain be associated with 2 or more secondary criteria: change in stool frequency, change in stool form, and changes related to defecation. Where previously the criteria stated that pain should lessen with defecation, Rome IV recognizes that pain may, in fact, increase. Of note, among English-speaking populations, use of Rome IV criteria led to an approximate 50% decrease in IBS prevalence in a recent study.²

The updated criteria of Rome IV also change some aspects of IBS classification. 鈥淭hese are changes in the way that subtypes of IBS are diagnosed, which often dictate what treatment is appropriate鈥攚hich drugs, especially,鈥� says Dr. Whitehead. Although still classified by the predominant bowel habit (constipation, diarrhea, mixed, or unclassified), in Rome IV the bowel habits are based on the proportion of days (>25%) on which abnormal stools occur. In Rome III, the 25% threshold of abnormal to normal stools covered all bowel movements.^1,2

Over time, 鈥渕any patients have normal bowel movements and then they may be classified as IBS-undetermined, and that鈥檚 not a good target for treatment,鈥� notes Douglas A. Drossman, MD, emeritus co-director of the UNC Center for Functional GI and Motility Disorders, and president of the Rome Foundation.

The new criteria offer a multicultural approach

The Rome IV criteria reflect updates to previous iterations through peer review and inclusion of research published since the earlier version. Importantly, the criteria are symptom-based, which places the patient鈥檚 experience at the center of diagnosis and management. As defined, a symptom is an experience that patients perceive as abnormal, whereas a syndrome is a 鈥渃onsistent association of symptoms.鈥�² Recognizing that the term functional is nonspecific and may stigmatize patients, an important step was to redefine FGIDs as disorders of gut-brain interaction (DGBI). The full definition covers disorders, including IBS, 鈥渃lassified by GI symptoms related to any combination of motility disturbances, visceral hypersensitivity, altered mucosal and immune function, gut microbiota, and/or central nervous system processing.鈥�²

A second global change was the inclusion of a multicultural approach, refined with the help of 117 experts from 23 nations worldwide. The goal here was to expand clinicians鈥� thinking to include patients鈥� values, beliefs, norms, and practices, as well as different cultural approaches to food, illness, and reporting of symptoms. For instance, in the US, patients have a sense of what abdominal discomfort entails, whereas in many foreign countries the word 鈥渄iscomfort鈥� has no translation. The same applies to 鈥渂loating,鈥� a term that seems to be confined mostly to the English language.²

According to Dr. Whitehead, 鈥淥ur job was, in part, to develop a diagnostic questionnaire based on criteria that committees of experts developed for making these diagnoses. Developing these materials was a multiyear process to be sure it was understandable and translatable to other languages, and that it was valid in the sense that it agrees with the diagnosis of expert clinicians.鈥�

Published: December 22, 2017