Is irritable bowel syndrome a diagnosis of exclusion?: a survey of primary care providers, gastroenterologists, and IBS experts

Abstract

Objectives: 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.

Methods: 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.

Results: 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.

Conclusions: 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.

Figure 1

Willingness to diagnose irritable bowel syndrome (IBS) on the basis of patient history and physical examination fi ndings alone in D-IBS vignette. Providers were asked: “Based upon the information provided to this point, do you believe that this patient has irritable bowel syndrome?” The fi gure depicts the percentages by group responding “Yes,” “No,” or “Unsure—need more information.” Among those answering “Yes,” we further explored willingness to inform the patient of the presumed diagnosis by asking: “In addition to believing that this patient has IBS, are you also prepared at this time to confi dently and affi rmatively inform her that she has IBS?” The light blue of the “Yes” bar demonstrates the subset prepared to make a confi dent and affi rmative diagnosis without further diagnostic testing.

Figure 2

Provider appropriateness ratings for performing common diagnostic tests in D-IBS vignette. Respondents scored the appropriateness of each test using a standard nine-point RAND/UCLA Appropriateness Scale, in which a score of 1–3 is “generally inappropriate,” 4–6 is “neither appropriate nor inappropriate,” and 7–9 is “generally appropriate.” Mean scores exceeding 6 indicate that providers believe, on average, that a test is generally appropriate; mean scores below 3 indicate that providers believe a test is generally inappropriate. CBC, complete blood count; ESR, erythrocyte sedimentation rate; D-IBS, irritable bowel syndrome with diarrhea; O&P, ova and parasites; TSH, thyroid-stimulating hormone; WBC, white blood cells.

Figure 3

Willingness to diagnose irritable bowel syndrome (IBS) on the basis of patient history and physical examination fi ndings alone in C-IBS vignette. IBS experts were more likely to believe the patient had IBS vs. nonexperts (72 vs. 20%; P < 0.0001). Refer to Figure 1 legend for interpretation. *White bar indicates percentage of experts who believe the patient has IBS. Light blue bar indicates sub-percentage who both believes patient has IBS and is willing to inform the patients without further testing.

Figure 4

Provider appropriateness ratings for performing common diagnostic tests in C-IBS vignette. Refer to Figure 2 legend for interpretation. ARM, anorectal manometry; CBC, complete blood count; TSH, thyroid-stimulating hormone.