Background & aims: Irritable bowel syndrome (IBS) is one of the most common gastrointestinal (GI) disorders, affecting about 10% of the general population globally. The aim of this consensus was to develop guidelines for the management of IBS. Methods: A systematic literature search identified studies on the management of IBS. The quality of evidence and strength of recommendations were rated according to the Grading of Recommendation Assessment, Development and Evaluation (GRADE) approach. Statements were developed through an iterative online platform and then finalized and voted on by a multidisciplinary group of clinicians and a patient. Results: Consensus was reached on 28 of 31 statements. Irritable bowel syndrome is diagnosed based on symptoms; serological testing is suggested to exclude celiac disease, but routine testing for C-reactive protein (CRP), fecal calprotectin or food allergies is not recommended. A trial of a low fermentable oligosaccharides, disaccharides, monosaccharides, polyols (FODMAP) diet is suggested, while a gluten-free diet is not. Psyllium, but not wheat bran, supplementation may help reduce symptoms. Alternative therapies such as peppermint oil and probiotics are suggested, while herbal therapies and acupuncture are not. Cognitive behavioural therapy and hypnotherapy are suggested psychological therapies. Among the suggested or recommended pharmacological therapies are antispasmodics, certain antidepressants, eluxadoline, lubiprostone, and linaclotide. Loperamide, cholestyramine and osmotic laxatives are not recommended for overall IBS symptoms. The nature of the IBS symptoms (diarrhea-predominant or constipation-predominant) should be considered in the choice of pharmacological treatments. Conclusions: Patients with IBS may benefit from a multipronged, individualized approach to treatment, including dietary modifications, psychological and pharmacological therapies.# 
Irritable bowel syndrome (IBS) is one of the most common gastrointestinal (GI) disorders. It is characterized by recurrent abdominal pain and altered bowel habits (i.e., constipation, diarrhea or both), often with associated bloating (1).
Globally, IBS is estimated to affect about 10% of the general population, but prevalence rates are highly variable (2,3). From country to country, the prevalence ranges from 1.1% to 45.0% but has been estimated at 12% (95% CI, 7%-17%) generally in North America (2), with a similar prevalence in Canada specifically (4). Rates also vary according to diagnostic criteria (2)(3)(4)(5). A large survey, across the United States, United Kingdom and Canada found that the Rome IV (~6%) prevalence rates were significantly lower than Rome III rates (~11%) in all countries (5). Women appear to be affected about 1.5 to two times more often than men, and the prevalence appears to decrease with increasing age (2)(3)(4)(5).
The current recommended diagnostic criteria for IBS are the Rome IV criteria: abdominal pain (1 day per week for 3 months) associated with defecation or a change in bowel habits (1,6). Irritable bowel syndrome is then subtyped according to the abnormality of stool consistency, including constipation-predominant (IBS-C, >25% hard stools and 25% loose stools and 25% loose stools and >25% hard stools); and unclassified (IBS-U <25% loose stools and <25% hard stools) (1). However, the available randomized clinical trials (RCTs) have used a variety of criteria, including Manning, Rome I, II, III, IV or questionnaire-defined. Therefore, for this consensus, IBS was pragmatically defined as abdominal pain associated with change in bowel habit for at least three months, and studies were included if they met this definition, regardless of criteria used. When diagnosing IBS, a full history and relevant examination are recommended, with limited use of diagnostic tests as discussed in the recommendations section of this consensus.
There have been guidelines on the management of IBS (7,8), but there has been an emergence of new therapies and new RCTs on current therapies because these guidelines have been published. The purpose of this guideline is to critically review the literature relating to diagnostic testing and the psychological and pharmacological treatment of IBS and to develop a consensus on specific recommendations for patients with any IBS, IBS-C or IBS-D.

# METHODS

# Scope and Purpose
These consensus statements focused on specific questions, identified and discussed by the participants, regarding the management of IBS. The development of this clinical practice guideline began in January 2017, with the full consensus group participating in a face-to-face meeting in May 2017; supplementary statements on breath testing were added after the meeting.

# Sources and Searches
The editorial office of the Cochrane Upper Gastrointestinal and Pancreatic Diseases Group at McMaster University performed a systematic literature search of MEDLINE (1946to March 2017, EMBASE (1980to March 2017, and CENTRAL (Cochrane Central Register of Controlled Trials). Evidence was first gathered from the most recently published, high-quality systematic reviews (primarily from the American College of Gastroenterology monograph published in 2014 (7), on which PM was a co-author). These meta-analyses were then updated with any further data identified in the literature searches up to March 2017. The updated search strategies are described in Appendix 1 online. Study inclusion criteria were parallel group RCTs (crossover studies were included if the data were available from the first period such that parallel group data could be obtained), using any definition of IBS, including a dichotomous outcome measure relating to global IBS symptom improvement, human studies, and English publications. Further details regarding the search strategies used for preparing the initial consensus statements can be found in Appendix 1 online. Two additional systematic searches (up to May 2017) were performed after the consensus meeting to address statements eight and nine, with key search terms including irritable bowel syndrome, breath tests, and lactose intolerance.

# Review and Grading of Evidence
A methodologist (PM) used the GRADE (Grading of Recommendation Assessment, Development and Evaluation) approach (9) to assess the risk of bias (of individual studies and overall across studies), indirectness, inconsistency, imprecision and other considerations (including publication bias) to determine the overall quality of evidence for each statement. The quality of evidence (QoE) for the individual statements was classified as high, moderate, low or very low as described in GRADE methodology (9,10) and used in prior Canadian Association of Gastroenterology (CAG) consensus documents (11)(12)(13)(14)(15)(16). GRADE assessments were validated by a second, nonparticipating methodologist, then reviewed and agreed upon by voting members of the consensus group at the meeting.
Approved product labeling from government regulatory agencies varies from country to country, and though not ignored, recommendations are based on evidence from the literature and consensus discussion and may not fully reflect the product labeling for a given country.

# Consensus Process
This Canadian consensus group consisted of 12 voting participants with experience in the area of IBS, including the chair (PM), gastroenterologists, general practitioners, a psychiatrist, a psychologist, a patient representative, and the moderator (also a gastroenterologist, WP).
The CAG web-based consensus platform (ECD solutions, Atlanta, Georgia, USA) was used to initiate the consensus process before the face-to-face consensus meeting held in Chicago, Illinois, USA in May 2017. The meeting chair (PM) and the steering committee (CA, GM, CK and the patient-representative ) developed the initial questions. The voting members then used the web-based platform to vote on their level of agreement and provide comments on the questions which were to be used to develop the recommendation statements during the meeting. A summary report of the literature search results was provided to the participants before the meeting.
At the meeting, the methodologist/chair (PM) presented the data and provided the group with a review of the GRADE evaluations which informed the quality of evidence determination for each of the questions. Recommendation statements were developed that were subsequently voted on anonymously via touchpads. A statement achieved consensus and was accepted if 75% of participants voted four (agree) or five (strongly agree) on a scale of one to five (with one, two, and three indicating disagree strongly, disagree, and neutral, respectively). Following acceptance of a statement, participants voted on the strength of the recommendation. A level of agreement of 75% of participants was needed to classify a statement as 'strong' (we recommend); if this threshold was not met, the statement defaulted to 'conditional' (we suggest). The strength of the recommendation considered risk-benefit balance, patients' values and preferences, cost and resource allocation, and the quality of the evidence. Therefore, it was possible for a recommendation to be classified as strong despite having low-quality evidence or conditional despite the existence of high-quality evidence (17). A strong recommendation is indicative of a more broadly applicable statement ('most patients should receive the recommended course of action'), whereas a conditional recommendation suggests that clinicians should 'recognize that different choices will be appropriate for different patients and that they must help each patient to arrive at a management decision consistent with her or his values and preferences' (17).
At the meeting, the group did not reach consensus on three of the initial 31 statements (no recommendation A-C); thus, these statements were rejected. The evidence has been discussed in the text, but the consensus group did not make a recommendation (neither for nor against) offering these treatments to IBS patients.
The initial manuscript was drafted by the meeting chair/ methodologist (PM) and was then reviewed and revised by the remaining members of the consensus group. The manuscript was made available to all CAG members for comments for a two-week period before submission for publication, as per CAG policy for all clinical practice guidelines.
In accordance with CAG policy, written disclosures of any potential conflicts of interest for the 24 months before the consensus meeting were provided by all participants and made available to all group members.

# Role of the Funding Sources