MISSING CELIAC DISEASE IN FAMILY MEDICINE: THE IMPORTANCE OF HYPOTHESIS GENERATION

PURPOSE Delays in diagnosing celiac disease in primary care average 13 years. We aimed to identify reasons for misdiagnosis at first presentation. METHODS As part of a larger study on diagnostic error, a scenario was constructed that described a 30-year old female presenting to the family physician with 3-months abdominal pain. The scenario was presented on computer to 84 GPs, who could request further information in order to diagnose. They could thus discover that the patient had irritable bowel syndrome (IBS)-type symptoms and microcytic anemia consistent with celiac disease. The computer recorded each physician's information gathering, diagnoses and management. Fifty physicians misdiagnosed (60%) and 38 of these were subsequently interviewed using a ‘stimulated recall' methodology. They were presented with a record of their information gathering, step by step, and were asked to recall: their diagnostic hypotheses, reasons for asking each piece of information, and how they interpreted it. Interviewees were unaware of the misdiagnosis. Analyses of the transcripts focused on three factors as potential reasons for misdiagnosis: 1. Consideration of celiac disease as a hypothesis during the workup. 2. Interpretation of ‘critical' cues (cues with LR>1.5 or <0.67). 3. Over-interpretation of non-critical cues. Two raters assessed critical cue interpretation against the published evidence, independently, in all the transcripts (Kappa=0.85). RESULTS No physician changed his/her earlier diagnosis during stimulated recall. Only ten physicians mentioned celiac disease as a diagnostic hypothesis (26%). ‘Diarrhea' and ‘pain relief by defecation' are diagnostic features of both celiac disease and IBS but were only linked to IBS. This explains why physicians who considered celiac disease failed to find evidence for it. ‘Absence of weight loss' was used to exclude celiac disease, though it is a feature of advanced disease. When a complete blood count was requested, it was never in order to test for celiac disease. In the absence of a specific hypothesis, ‘microcytic anemia', the only patient feature that discriminated between IBS and celiac disease, was explained away, or given as a separate diagnosis. CONCLUSIONS In the absence of feedback, reviewing the case during stimulated recall did not result in re-evaluating the evidence and changing the diagnosis. The most important reason for missing celiac disease in this presentation was not considering it as a diagnostic hypothesis and ignoring inconsistent information.