Editorial
The American Journal of Gastroenterology
October 1999
Volume 94, Number 10
Pages 2803-2807
The Rome Criteria Process: Diagnosis and Legitimization of Irritable Bowel Syndrome
Douglas A. Drossman, M.D. a
The irritable bowel syndrome (IBS), the functional GI disorder most familiar to physicians, has become de rigeur. Over the last two decades, there has been a 10-fold increase in citations on IBS (1). The National Institutes of Health (NIDDK), various gastroenterology societies, the Digestive Health Initiative, and the International Foundation for Functional GI Disorders (IFFGD) have increased the exposure of IBS through educational and research programs. Even though the pathophysiology of IBS is poorly understood, this exposure has attracted the interest of basic scientists, physiologists, clinical investigators in gastroenterology, and mental health professionals who are working to improve our scientific understanding of this common disorder. Most recently, the pharmaceutical industry has begun international marketing campaigns to increase physician and public awareness of IBS, expecting that the new enteric receptor active agents, now completing phase II and III trials, will help treat the large potential market of IBS sufferers.
Is the IBS a 'Real' Entity?
But what is the IBS? Is it a true disorder with a pathophysiological basis? And can it be diagnosed with confidence? For centuries, physicians have recognized that persons commonly experience abdominal pain, bloating, diarrhea, constipation, urgent or difficult passage of feces, or any combination (2). When these symptoms are severe enough to impact on daily life, they are perceived as an illness that may require medical care. Traditionally, physicians seeing these patients have searched for inflammatory, infectious, neoplastic, and other structural abnormalities to make a diagnosis (of a disease) and to provide specific treatment. But, when no such etiology is disclosed, the patient is diagnosed, by exclusion, to have a 'functional' disorder, and is treated symptomatically.
Thus, the IBS fits in that grey zone of medicine: an "illness without disease," and this poses certain dilemmas (3). First, there is the dilemma of how to make a diagnosis when no disease-based biological marker exists. Excluding a disease through negative studies does not truly diagnose a medical disorder any more than it fully eliminates the possibility that an occult disease is still present. Yet, the data show that most symptoms brought to the medical physician are not explained by specific structural abnormalities (4). Second, there is the dilemma of how to communicate this type of information to the patient. If the physician is uncertain about the diagnosis, he/she may order additional unneeded studies, which can heighten the patient's concerns that something is being missed (5). Or, with no biological evidence for a disease, the physician may inadvertently discount the validity of the complaints ("There's nothing wrong"), and feel insecure about how to provide optimal care ("You'll have to learn to live with it"). Even worse, the physician may develop unproductive attributions toward the patient or the illness (now possibly considered "psychosomatic") that are reflected in the plan of care (e.g., "Relax, it's your nerves," or "Maybe you need to see a psychiatrist"). Of course, when the patient is not given a confident diagnosis and plan or care, or feels not believed or stigmatized, he or she may get angry or lose confidence in the physician, and will usually seek help elsewhere. All of this perpetuates an ineffective physician-patient interaction and a marginally effective plan of care (6). Finally, there is the dilemma of how to identify patients for clinical trials and other research studies. It is not practical to define IBS by exclusion, because this leads to heterogeneous groups that cannot be compared across study sites. What is needed is a valid and reliable method to diagnose IBS, both for clinical practice and for the selection of study subjects for clinical research. But how can you define a medical disorder in the absence of a biological "gold standard"?
A New Perspective on IBS
Over the last two decades, three important processes have evolved to help us understand the IBS as a bona fide clinical entity. The first has been a change in how we conceptualize medical disorders. We are moving from an antiquated, disease-based, reductionistic model that seeks to find a single underlying biological etiology for illness, to a more integrated, biopsychosocial or systems model of illness and disease (3, 7). The biopsychosocial model provides the structure to understand the multidetermined nature of IBS (e.g., as the integrated product of altered motility, enhanced visceral sensitivity, and brain-gut dysregulation, as modified by psychosocial influences), and to treat the patients using multicomponent methods (e.g., diet, intestinal and centrally acting medications, psychological/behavioral treatments).
A second, concurrent process has been the expansion and refinement of investigative methods that allow us to study the multidetermined nature of IBS and, by this process, to affirm its existence. This includes: a) improved motility assessment, b) the standardization of the barostat to measure visceral sensitivity (8), c) the introduction of brain imaging (PET, fMRI) to determine the central nervous system contribution to symptoms (9, 10), d) the use of standardized psychometric instruments to determine psychosocial influences on the condition (11), and e) the molecular investigation of brain-gut peptides (12), which provides insight into how these symptoms become manifest. In 10 yr, these methods have produced new knowledge of the underlying pathophysiological features that characterize the age-old symptoms that we now define as IBS.
The Rome Criteria
The third process involves an international effort to characterize and to classify the functional gastrointestinal disorders using a symptom-based classification system, now called the Rome criteria (13, 14). The rationale for such a classification scheme is based on the premise that patients with functional GI complaints consistently report symptoms that "breed true" in their clinical features, yet they cannot be classified by any existing structural, physiological, or biochemical substrate. A symptom-based approach has its precedent with classification systems in psychiatry and rheumatology, and is in common use around the world. So, in the absence of laboratory markers, persons with anorexia nervosa, panic disorder, or fibromyalgia, as examples, are recognized by their symptoms or behaviors; these features define clinical populations that can be reliably investigated and that are amenable to specific treatments. For IBS and the other functional GI disorders, the use of a symptom-based diagnostic approach is supported by epidemiological data that show agreement in the frequency of certain symptom groups across populations (15). In addition, factor analytic studies consistently identify symptom clusters similar to those developed through empirically derived clinical studies. For example, using factor analysis of 500 nonclinical subjects, Whitehead et al. (16) identified an IBS factor (abdominal pain relieved by defecation and associated with a change in the frequency and consistency of stool). This was similar to the original Manning criteria developed from discriminant function analysis of gastroenterology patients (17), thereby providing concurrent validity. These and other studies are the basis for the IBS Rome criteria. The decision to develop diagnostic criteria by international consensus was introduced by Professor Aldo Torsoli for the International Congress of Gastroenterology held in Rome in 1988 (Roma '88). As part of a larger effort to address issues within gastroenterology that are not easily resolved by the usual scientific inquiry or review of the literature, the approach was to have working committees solve problems using the "Delphi" method of consensus (18). One of the committees, chaired by W. Grant Thompson of Canada, was charged to develop diagnostic guidelines for IBS. The committee built upon the Manning criteria published 10 yr earlier (17) and other epidemiological studies to produce a document that defined and characterized the IBS, recommended a diagnostic approach that included symptom-based criteria, and provided recommendations for treatment (19). The following year, a new Working Team Committee went on to develop a complete classification system with diagnostic and treatment guidelines for all of the functional GI disorders (20). Over the next 4 yr, several subcommittees published details on the epidemiology, physiology, diagnostic evaluation, and treatments of these newly classified disorders, and also produced documents on the design of treatment trials and on the psychosocial aspects of the functional GI disorders. From 1992 to 1994, seven articles appeared in Gastroenterology International; these were compiled, updated, and expanded in a book published in 1994 (Rome I) (13).
Limitations to the Rome Criteria.
A symptom-based classification system has potential limitations. The first limitation is that the criteria are developed by consensus rather than by an external diagnostic ("gold") standard. Even "expert" clinicians and investigators have different training, experience, and personal biases. Furthermore, consensus, when achieved, can only provide face validity. Therefore, additional validation studies are needed to support clinical impressions. Second, symptoms alone are not specific enough for a diagnosis, and the high frequency of functional GI disorders in clinical practice also assures their coexistence with other diseases. So, it is still necessary to exclude other medical disorders having similar clinical presentations (e.g., Crohn's disease) that will respond to different treatments. This raises the question as to whether this classification scheme might help to reduce the number of unneeded diagnostic studies, thereby increasing physician and patient satisfaction and reducing costs. Finally, there is the risk that the acceptance of these criteria in research and clinical practice might become a self-fulfilling prophecy. The published definitions and criteria for IBS and other functional GI disorders may become so familiar that, as new scientific data emerge, the capability to change them might be impaired (21).
The first two of these limitations were addressed by Vanner et al. in the Journal (22). The authors tested the ability of the Rome I criteria to predict IBS using the gastroenterologists' evaluation as the "gold standard." Using both retrospective and prospective designs, they determined the degree to which referred patients who met Rome Criteria in the absence of "red flags" (weight loss, nocturnal symptoms, blood in the stools, abnormal physical examination, family history of colon cancer, recent antibiotic use) were successfully diagnosed by gastroenterology consultants to have IBS. Patients were followed-up for 2 yr. In the retrospective study, use of the Rome criteria, and the absence of "red flags" yielded a sensitivity of 63% and a specificity of 100%, with a positive predictive value (PPV) of 100%. In the prospective study the PPV was 98% (one patient was found to have proctitis and the other was hyperthyroid), which is greater than the PPV of studies evaluating the Manning (17) and Kruis (23) criteria (22). Because the high PPV might result from the use of "red flags" that exclude obvious disease, the authors performed further analyses. They found that adding the Rome criteria to the "red flags" more than doubled the PPV.
It is noteworthy that the false negative rate was 16% (i.e., 16% of patients not meeting criteria were diagnosed as having IBS by the gastroenterologists) and the negative predictive value was 76%. The sensitivity of the Rome criteria tend to be lower than the Manning and Kruis criteria, in part because the Rome Criteria were originally designed for clinical trials and tend to be more restrictive. However, it is also possible that, if physicians are not adequately trained in the diagnosis of IBS, they might mislabel other functional GI disorders (e.g., painless diarrhea or chronic functional abdominal pain) as IBS.
Overall, the data help to validate the Rome criteria. They provide preliminary evidence that the Rome Criteria, along with a good physical examination and a few ("red flag") clinical questions, can diagnosis IBS for clinical practice and research and may reduce unneeded diagnostic studies. Finally, because the criteria are more restrictive, some clinicians may still diagnose IBS in patients who do not meet the criteria.
Rome II and Beyond
The Rome committee organization is currently addressing the third limitation: that clinicians and investigators may become complacent in the use of these criteria as new scientific data emerge to challenge them. In 1996, the Multinational Working Teams to Develop Diagnostic Criteria for Diagnosis of Functional GI Disorders was established to allow for the communication of new scientific knowledge in the field of functional GI disorders, and for the revision of diagnostic criteria as new data emerge. Building upon its previous (Rome I) activities, the Rome II Coordinating Committee* set up several objectives: 1) to update, summarize and publish the new knowledge on the functional GI disorders; 2) to revise the original Rome Criteria, if needed, based on new scientific data; 3) to set up a process for future validation of the Rome II criteria; and 4) to help support, promote, and legitimize the field of functional GI disorders.
All of these objectives are being achieved. The Rome II documents include a book (14) and a journal supplement in Gut (24), that resulted from a 4-year process, involving 10 committees of 52 members, representing 13 countries. The book is a comprehensive reference that addresses current research, practical recommendations on diagnosis and treatment of the functional GI disorders, sections on basic science, physiology, design of treatment trials and clinical outcomes, psychosocial aspects, and a new classification system for childhood functional GI disorders. Diagnostic questionnaires are also included for use in research and patient care. The journal supplement contains the diagnostic criteria and an abbreviated version of the committees' recommendations.
The quality control that led to these publications was implemented in several ways (15): 1) guidelines for creating the documents were standardized across committees and were overseen by the administrative office; 2) the documents were revised at least five times, twice before the face-to-face meeting in Rome, once right after the meeting, once in response to the outside reviews, and once (to achieve consistency in presentation style) after review by the Coordinating Committee; 3) critical review of the documents was provided by a minimum of six reviewers for each committee, in addition to several pharmaceutical companies, the NIDDK, and the Food and Drug Administration. All critical comments had to be addressed in writing by the committee chair after review with his committee; 4) to avoid arbitrary changes in previous diagnostic criteria, no modifications in the criteria could be made unless they were evidence-based; and 5) finally, all committee members signed statements saying that they agreed with the content of the final document.
To address the issue of validation, the Coordinating Committee set up an Extramural Grants Program, to promote and support validation studies relating to the criteria. To date, five grants have been awarded and all studies are currently underway. In addition, a recent factor analytic study supports the current Rome classification system (25).
To help promote the field of functional GI disorders, the criteria have already helped to standardize the selection of patients into clinical trials. Recently, collaborations have been set up with pharmaceutical companies and regulatory agencies to provide assistance in the design of future clinical trials and the assessment of clinical outcomes. Efforts are now being made to update the ICD-9 and 10 diagnostic classification systems. Hopefully, antiquated terms like "mucous colitis" will be replaced by more accepted terms.
Finally, the use of symptom-based criteria by clinicians and investigators may help to legitimize these disorders to physicians, patients, and society. Vanner et al. (22) has shown that use of the criteria may decrease unneeded diagnostic studies. Physicians who make a diagnosis with confidence may also feel able to educate the patient and to communicate more effectively that the symptoms are "real" and manageable. In the end, when patients accept and understand their symptoms, they may not need to see physicians as often (26), and this will be associated with improved satisfaction in their care, a greater sense of control over their disorder, and ultimately lower health care costs.
a Co-Director, UNC Center for Functional GI and Motility Disorders, Division of Digestive Diseases, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
References
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Reprint requests and correspondence: Douglas A. Drossman, M.D., Co-Director, Division of Digestive Diseases, Department of Medicine, University of North Carolina at Chapel Hill, 726 Burnett-Womack Building, CB #7080, Chapel Hill, NC 27599-1080.
Received July 9, 1999; accepted July 9, 1999.
* Coordinating Committee of the Multinational Working Teams for Diagnosis of Functional GI Disorders (Rome II): Douglas A. Drossman, M.D. (chair), USA; Enrico Corazziari, M.D., Italy; Nicholas J. Talley, M.D., M.P.H., Australia; W. Grant Thompson, M.D., Canada; and William E. Whitehead, Ph.D., USA.
Copyright ©1999 the American College of Gastroenterology
Published by Elsevier Science Inc.
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