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Probiotics are effective treatments for IBS, although which individual species and strains are the most beneficial remains unclear. Further evidence is required before the role of prebiotics or synbiotics in IBS is known. The efficacy of all three therapies in CIC is also uncertain.

IntroductionIrritable bowel syndrome (IBS) is the most prevalent of the functional gastrointestinal disorders (FGIDs). Current estimates are that IBS affects up to 10-12% of adults in North America (1,2). Although it can affect all individuals regardless of age, creed, or gender, IBS is more common among women and is most commonly diagnosed in younger individuals (< age 50) (2, 3). IBS is characterized by recurrent abdominal pain and altered bowel habits; bloating and distention frequently coexist. The diagnosis of IBS is made by taking a careful history, eliciting key symptoms, as well as performing a physical examination and limited diagnostic testing (4-6). IBS is categorized into four main subtypes based on the predominant bowel habit: IBS with constipation (IBC-C); IBS with diarrhea (IBS-D); IBS with mixed symptomology (IBS-M); and unclassified IBS (5).IBS imposes a significant burden to the health care system and to individuals.Direct medical costs attributed to IBS in the US, excluding prescription and over-thecounter medicines, were estimated at $1.5-$10 billion per year in 2005 (7). Patients with IBS enrolled in a large Health Maintenance Organization (HMO) had significantly more outpatient visits and incurred nearly 50% more in total costs than individuals without IBS (8). A retrospective case-control study from another large HMO reported that patients with IBS had significantly more diagnostic tests, imaging, and surgery compared with patients without a diagnosis of IBS (9). Significant variations in care across the United States related to the diagnosis and treatment of IBS also play a role in excessive health care costs (10). The burden of IBS on individuals can be measured in a number of ways. Studies have demonstrated consistently that IBS impairs work-related activities (e.g., lost work time, reduced productivity while at work) and also reduces quality of life (11,12). The development Ford et al.Page 3 of 91 of effective and efficient treatment strategies for IBS assumes considerable importance, therefore, not just for the individual sufferer, but for society at large.Given the clinical heterogeneity that is a hallmark of the disorder and the absence of a single effective therapy for all sufferers, available therapies tend to focus on predominant symptomatology at presentation (i.e., altered bowel habits, abdominal pain, or bloating) (4-6). Based on their purported mode of action, many pharmacological therapies for IBS developed in recent decades have been directed towards those with a particular bowel habit, whether diarrhea or constipation.However, treating IBS patients can be difficult as no validated treatment algorithm exists, not all patients respond to treatment, and patients with similar symptoms frequently respond to the same treatment differently. Fortunately, a variety of novel therapeutic strategies are being explored and new compounds have appeared since the last iteration of the ACG monograph on IBS (4). The goal of this document, therefore, is to provide an updated, evidence-based d...

Antidepressants and some psychological therapies are effective treatments for IBS. Despite the considerable number of studies published in the intervening 5 years since we last examined this issue, the overall summary estimates of treatment effect have remained remarkably stable.

OBJECTIVE:The aim of this study was to systematically review published literature about the prevalence, incidence, and natural history of irritable bowel syndrome (IBS) in North America. METHODS:A computer-assisted search of MEDLINE, EMBASE, and Current Contents/Science Edition databases was performed independently by two investigators. Study selection criteria included: 1) North American populationbased sample of adults; 2) objective diagnostic criteria for IBS (i.e., Rome or Manning criteria); and 3) publication in full manuscript form in English. Eligible articles were reviewed in a duplicate and independent manner. Data extracted were converted into individual tables and presented in descriptive form. RESULTS:The prevalence of IBS in North America ranges from 3% to 20%, with most prevalence estimates ranging from 10% to 15%. The prevalences of diarrhea-predominant and constipation-predominant IBS are both approximately 5%. Published prevalence estimates by gender range from 2:1 female predominance to a ratio of 1:1. Constipationpredominant IBS is more common in female individuals. The prevalence of IBS varies minimally with age. No true population-based incidence studies or natural history studies were found. In one cohort surveyed on two occasions 1 yr apart, 9% of subjects who were free of IBS at baseline reported IBS at follow-up producing an onset rate of 67 per 1000 person-years. In all, 38% of patients meeting criteria for IBS did not meet IBS criteria at 1-yr follow-up. CONCLUSION:Approximately 30 million people in North America meet the diagnostic criteria for IBS. However, data about the natural history of IBS is quite sparse and renewed efforts should be focused at developing appropriately designed trials of the epidemiology of IBS. (Am J Gastroenterol 2002;97:1910 -1915

Background & Aims Anti-depressants are frequently prescribed to treat functional dyspepsia (FD), a common disorder characterized by upper abdominal symptoms, including discomfort or post-prandial fullness. However, there is little evidence for the efficacy of these drugs in patients with FD. We performed a randomized, double-blind, placebo-controlled trial to evaluate the effects of anti-depressant therapy effects on symptoms, gastric emptying (GE), and mealinduced satiety in patients with FD. Methods We performed a study at 8 North American sites of patients who met the Rome II criteria for FD and did not have depression or use anti-depressants. Subjects (n=292; 44±15 y old, 75% female, 70% with dysmotility-like FD, and 30% with ulcer-like FD) were randomly assigned to groups given placebo, 50 mg amitriptyline, or 10 mg escitalopram for 10 weeks. The primary endpoint was adequate relief of FD symptoms for ≥5 weeks of the last 10 weeks (out of 12). Secondary endpoints included GE time, maximum tolerated volume in a nutrient drink test, and FD-related quality of life. Results An adequate relief response was reported by 39 subjects given placebo (40%), 51 given amitriptyline (53%), and 37 given escitalopram (38%) (P=.05, following treatment, adjusted for baseline balancing factors including all subjects). Subjects with ulcer-like FD given amitriptyline were more than 3-fold more likely to report adequate relief than those given placebo (odds ratio=3.1; 95% confidence interval, 1.1–9.0). Neither amitriptyline nor escitalopram appeared to affect GE or meal-induced satiety after the 10 week period in any group. Subjects with delayed GE were less likely to report adequate relief than subjects with normal GE (odds ratio=0.4; 95% confidence interval, 0.2–0.8). Both anti-depressants improved overall quality-of-life. Conclusions Amitriptyline, but not escitalopram, appears to benefit some patients with FD— particularly those with ulcer-like (painful) FD. Patients with delayed GE do not respond to these drugs.

There is insufficient evidence to recommend a GFD to reduce IBS symptoms. There is very low quality evidence that a low FODMAP diet is effective in reducing symptoms in IBS patients.

Soluble fiber is effective in treating IBS. Bran did not appear to be of benefit, although we did not uncover any evidence of harm from this intervention, as others have speculated from uncontrolled data.