American College of Gastroenterology Monograph on Management of Irritable Bowel Syndrome

Abstract

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...

Review article: an analysis of safety profiles of treatments for diarrhoea‐predominant irritable bowel syndrome

“…In addition, a survey‐based study noted that 73% of 1094 individuals diagnosed with IBS‐D reported avoiding foods that they thought would cause stomach upset . The number needed to treat, or the number of patients needed for one patient to achieve improvement of symptoms with treatment (relative to control), is 5 for the low FODMAP diet compared with an alternative diet (n = 7 studies; quality of evidence was considered “very low”); the number needed to treat for a gluten‐free diet cannot be calculated accurately …”

“…The precise mechanism by which probiotics improve IBS symptoms is unknown; however, some patients may benefit from modulation of gut microbiota . A meta‐analysis of 37 randomised, controlled studies (n = 4403) reported that probiotics were significantly better than placebo for the improvement of IBS symptoms (relative risk of IBS not improving 0.81; 95% CI 0.74‐0.88) . Combination probiotic products were found to have significantly greater benefit than placebo (n = 21 randomised, controlled studies [1931 patients]; relative risk of IBS not improving, 0.79; 95% CI, 0.68‐0.91) .…”

“…Probiotics have a long history of safety (eg, in food products), but clinical trials of probiotics are inconsistent with regard to safety reporting, particularly in patients who may be at increased risk of AEs (eg, immunocompromised or hospitalised individuals, pregnant women) . A meta‐analysis of 36 randomised, controlled studies that included 4183 patients with IBS found no increased risk of AEs in patients receiving probiotics (relative risk 1.09; 95% CI 0.91‐1.29) . The number needed to harm for probiotics was 35 and based on patients experiencing an AE .…”

“…Most patients with constipation (75%) reported occurrence of this AE within the first 2 weeks of treatment . In one meta‐analysis of seven randomised, controlled studies of alosetron (n = 4607), constipation was the most common AE compared with placebo, with a number needed to harm of 5 for this individual AE . An adjudicated analysis of an alosetron postmarketing safety database (November 2002 to December 2011) identified 1.03 cases of ischaemic colitis and 0.25 cases of complications of constipation per 1000 patient‐years of exposure .…”

“…Available treatments for IBS‐D include dietary modification, probiotics, serotonin (5‐hydroxytryptamine type 3 [5‐HT 3 ]) receptor antagonists (eg, alosetron, ondansetron), opioid receptor agonists and antagonists (eg, loperamide, eluxadoline [Viberzi ® , Allergan, Irvine, CA]), nonsystemic antibiotics (eg, rifaximin [Xifaxan ® , Salix Pharmaceuticals, Bridgewater, NJ]), bile acid sequestrants (eg, cholestyramine, colesevelam), antidepressants (eg, tricyclic antidepressants, selective serotonin reuptake inhibitors), complementary and alternative medicine (eg, herbal therapies, mind‐body interventions [eg, cognitive behavioural therapy, hypnotherapy], and mechanical interventions [eg, yoga, acupuncture]). As no validated treatment algorithm exists for patients with IBS and diarrhoea, many treatments are frequently used to manage symptoms . Ideally, the selection of a therapy should be based on a careful assessment of both efficacy and adverse events (AEs).…”