IBS Diagnosis: Clinical Gestalt vs Clear-Cut Criteria

Critics complain that the diagnosis of irritable bowel syndrome (IBS) by primary care physicians (PCPs) is based on a vague clinical “gestalt” rather than rigorous clinical criteria. As a former practicing internist, I read this summary of the 2012 Multinational Irritable Bowel Syndrome Initiative with some sense of vindication. Twenty-nine of the world’s top IBS clinician-scientists participated in a survey and meeting that focused on the current state of the art in the diagnosis of IBS. Group members have written a total of 884 functional bowel publications (average number per participant was 27), and the authors of the study are noted leaders in the area.

Why do I feel vindicated? It turns out that the best specialists in the world struggle just as PCPs do-their IBS diagnoses tend to be gestalt-based, and they long for better, empirically based clinical criteria. 

The study had 2 phases, the first an online survey that asked participants to disclose their practice patterns without bias from other participants. The second phase was a face-to-face meeting during the American Gastroenterological Association’s Digestive Disease Week in San Diego in May 2012.

It turns out that 62% of these specialists diagnose IBS in their practices by using their “own clinical experience.” Another 23% said it was a “diagnosis of exclusion”; 51% use the Rome III criteria;  14% use the Manning criteria; and 11% use Rome II (responses weren’t required to be mutually exclusive so total exceeds 100%). Although specialists may be more aware of specific criteria for IBS than their generalist peers, clinical gestalt directs their diagnostic process most often. Interestingly, when these same experts were asked about inclusion criteria for clinical studies of IBS, virtually all of them indicated that they use the Rome criteria. 

Why the split?

Fully three-quarters (77%) indicated that they do not feel that the Rome criteria adequately reflect IBS as it occurs in their practices, and in the population at large. What did they identify as the key shortcomings of the Rome criteria? The current Rome criteria require abdominal pain or discomfort for at least 3 days per month in the past 3 months, associated with at least 2 of the following: (1) improvement with defecation; (2) onset associated with a change in stool frequency; or (3) onset associated with change in appearance of the stool. But the survey indicated that 54% of participants felt that bloating was the most important clinical feature in IBS-that’s what they’re hearing from their IBS patients. Only 29% felt that pain was the most important feature.

During the Digestive Disease Week on-site discussion, the specialist participants tended to agree that pain is not a primary feature of IBS and that reported pain or discomfort is directly linked to the amount of bloating and the extent of altered bowel function. The consensus was that future criteria should include bloating as a diagnostic criterion, and pain should be de-emphasized. There was also agreement that a major problem with the Rome criteria was its lack of multicenter/multinational validation.

The group lamented the lack of systematically developed clinical criteria and suggested validating future ones with multicenter/multinational research, and further, that specific biomarker development should be a focus for IBS clinical researchers. Without objective criteria for the condition, we are left with a vague set of questions and responses. What is pain? What is discomfort? Which patients overstate or understate the frequency of their symptoms?

IBS is difficult to identify and treat in primary care, but specialists and PCPs alike struggle with vagueness around this condition. For all practitioners, the message of this initiative was to pay more attention to bloating complaints. The message for IBS researchers (to themselves!) was to refine the criteria and develop biomarkers to solidify diagnosis for this very common condition. 

Reference
Pimentel M, Talley NJ, Quigley EM, et al. Report from the Multinational Irritable Bowel Syndrome Initiative 2012. Gastroenterology. 2013;144:e1-e5. (Read the abstract here.)