Is irritable bowel syndrome a diagnosis of exclusion?
Guidelines emphasize that irritable bowel syndrome (IBS) is not a diagnosis of exclusion and encourage clinicians to make a positive diagnosis using the Rome criteria alone. Yet many clinicians are concerned about overlooking alternative diagnoses. We measured beliefs about whether IBS is a diagnosis of exclusion, and measured testing proclivity between IBS experts and community providers. We developed a survey to measure decision-making in two standardized patients with Rome III-positive IBS, including IBS with diarrhea (D-IBS) and IBS with constipation (C-IBS). The survey elicited provider knowledge and beliefs about IBS, including testing proclivity and beliefs regarding IBS as a diagnosis of exclusion. We surveyed nurse practitioners, primary care physicians, community gastroenterologists, and IBS experts. Experts were less likely than nonexperts to endorse IBS as a diagnosis of exclusion (8 vs. 72%; P<0.0001). In the D-IBS vignette, experts were more likely to make a positive diagnosis of IBS (67 vs. 38%; P<0.001), to perform fewer tests (2.0 vs. 4.1; P<0.01), and to expend less money on testing (US$297 vs. $658; P<0.01). Providers who believed IBS is a diagnosis of exclusion ordered 1.6 more tests and consumed $364 more than others (P<0.0001). Experts only rated celiac sprue screening and complete blood count as appropriate in D-IBS; nonexperts rated most tests as appropriate. Parallel results were found in the C-IBS vignette.
Most community providers believe IBS is a diagnosis of exclusion; this belief is associated with increased resource use. Experts comply more closely with guidelines to diagnose IBS with minimal testing. This disconnect suggests that better implementation of guidelines is warranted to minimize variation and improve cost-effectiveness of care.