The latest iteration of the Rome criteria should improve diagnosis of irritable bowel syndrome, says Brian E. Lacy.
Irritable bowel syndrome (IBS) is one of the most common gastrointestinal conditions encountered by clinicians — globally, it afflicts around 11% of people of all races, sexes and socioeconomic status1. It is associated with recurrent abdominal pain linked with defecation, a change in bowel habits (constipation, diarrhoea or both), as well as other symptoms that do not seem to relate to the gut.
Despite its prevalence, IBS remains frustratingly difficult to diagnose. The leading reason is the lack of a good biomarker. The presence of multiple, overlapping non-specific symptoms (abdominal pain, bloating, distension, diarrhoea and constipation), related to the inherent heterogeneity of the disorder, complicates matters. Then there is the lack of understanding by clinicians about the condition, and the hesitance of patients and doctors to accept a symptom-based diagnosis.
During the late 1980s, efforts to improve the diagnosis of IBS and to standardize the diagnostic process led to the development of the Rome criteria2. The third iteration, Rome III, was published in 2006 (ref. 3) and at the time was felt to represent the most up-to-date data on the diagnosis and treatment of IBS. Rome III defined IBS as recurrent abdominal pain or discomfort at least three days per month in the preceding three months, which is associated with at least two of the following: symptom improvement with defecation, symptom onset coupled with altered stool frequency, or symptom onset coupled with altered stool form.
During the past decade, however, it became clear that Rome III needed revision, partly because research improved our understanding of how IBS develops and of its underlying pathophysiological changes. But perhaps most importantly, because many clinicians found that the Rome III criteria were not as useful as they had hoped, and that the guidelines did not reflect real-world practice. For example, Rome III did not recommend basic laboratory tests and ignored the fact that abdominal pain often worsens, rather than improves, with defecation. The criteria were also criticized for being mainly designed for researchers and not for the busy clinician, who frequently encounters patients exhibiting multiple symptoms — both intestinal and non-intestinal. Health-care providers reported that some of the Rome III criteria were either vague or incorrect. And some researchers and clinicians argued that Rome III did not fully distinguish constipation-predominant IBS from chronic constipation, or diarrhoea-predominant IBS from other causes of diarrhoea.
The new Rome guidelines4 aim to address these criticisms and to provide clearer guidance for health-care providers based on the latest clinical evidence. Published in May, Rome IV covers many functional bowel disorders, of which IBS is the most prevalent. It is the result of an exhaustive review of the literature and nearly three years of work by international specialists, including a team led by myself and Fermín Mearin of the Centro Médico Teknon in Barcelona, Spain, that focused exclusively on IBS.
Rome IV delivers several important changes in the diagnostic criteria for IBS. Gone is the term abdominal discomfort — the word discomfort is imprecise and is not present in every language. The criteria also require that abdominal pain is present at least one day per week on average during the preceding three months, up from just three days per month. This was based on a survey conducted on behalf of the Rome committee, which found that pain is the cardinal symptom of IBS4. These new criteria also recognize that IBS is often associated with irregular bowel habits — constipation, diarrhoea or a mix of both — and that common symptoms include bloating and distension. For a condition to be classified as IBS, it must be chronic, reflected by the addition that symptoms should have persisted for at least six months. The Rome criteria also now acknowledge the role of diagnostic tests to exclude other common conditions, such as coeliac disease, lactose intolerance and inflammatory bowel disease, which have similar symptoms to IBS.
By clarifying the language, updating the definition and including the option of laboratory testing, the new criteria should make it easier for doctors to diagnose IBS. The increased focus on abdominal pain reinforces what is reported by the clinicians who routinely care for these patients — that abdominal pain is the essential element of IBS. Rome IV will also help to distinguish people with IBS from those who have intermittent abdominal spasms or cramps, as well as from those who have chronic constipation or diarrhoea.
Tremendous advances have been made in our understanding of IBS over the past decade. Although it is a chronic disorder for many, and not yet curable, new therapeutic options have significantly improved the symptoms of many patients with IBS. The release of the Rome IV criteria should enhance clinicians' knowledge of this common disorder and allow them to more reliably diagnose it. In research laboratories too, a more refined definition will help scientists to identify and categorize people with IBS and its subtypes, improving our understanding of the complex physiology of the condition, and in turn, spur researchers to make even greater therapeutic discoveries.
This article is part of the Nature Outlook: IBS
About this article
Editorial: Clinical Implications of Diagnosing Irritable Bowel Syndrome: Do All Roads Need to Lead to Rome?
The American Journal of Gastroenterology (2017)