Evidence- and consensus-based practice guidelines for the diagnosis of irritable bowel syndrome

Background: Irritable bowel syndrome (IBS) presents a significant diagnostic and management challenge for primary care practitioners. Improving the accuracy and timeliness of diagnosis may result in improved quality and efficiency of care. Objective: To systematically appraise the existing diagnostic criteria and combine the evidence with expert opinion to derive evidence- and consensus-based guidelines for a diagnostic approach to patients with suspected IBS. Methods: We performed a systematic literature review (January 1966-April 2000) of computerized bibliographic databases. Articles meeting explicit inclusion criteria for diagnostic studies in IBS were subjected to critical appraisal, which formed the basis of guideline statements presented to an expert panel. To develop a diagnostic algorithm, an expert panel of specialists and primary care physicians was used to fill in gaps in the literature. Consensus was developed using a modified Delphi technique. Results: The systematic literature review identified only 13 published studies regarding the effectiveness of competing diagnostic approaches for IBS, the accuracy of diagnostic tests, and the internal validity of current diagnostic symptom criteria. Few studies met accepted methodological criteria. While symptom criteria have been validated, the utility of endoscopic and other diagnostic interventions remains unknown. An analysis of the literature, combined with consensus from experienced clinicians, resulted in the development of a diagnostic algorithm relevant to primary care that emphasizes a symptom-based diagnostic approach, refers patients with alarm symptoms to subspecialists, and reserves radiographic, endoscopic, and other tests for referral cases. The resulting algorithm highlights the reliance on symptom criteria and comprises a primary module, 3 submodules based on the predominant symptom pattern (constipation, diarrhea, and pain) and severity level, and a subspecialist referral module. Conclusions: The dearth of available evidence highlights the need for more rigorous scientific validation to identify the most accurate methods of diagnosing IBS. Until such time, the diagnostic algorithm presented herein could inform decision making for a range of providers caring for primary care patients with abdominal discomfort or pain and altered bowel function suggestive of IBS.