Brennan M. Spiegel

An Evidence-Based Position Statement on the Management of Irritable Bowel Syndrome

IBS is characterized by abdominal discomfort associated with altered bowel function; structural and biochemical abnormalities are absent. e pathophysiology of IBS is multifactorial and of intense recent interest, largely because of the possibility of developing targeted therapies. As IBS is one of the most common disorders managed by gastroenterologists and primary care physicians, this monograph was developed to educate physicians about its epidemiology, diagnostic approach, and treatments. e American College of Gastroenterology (ACG) IBS Task Force updated the 2002 monograph because new evidence has emerged on the bene* t and risks of drugs used for IBS. Furthermore, new drugs also have been developed and the evidence for e+ cacy of these drugs needed to be assessed. To critically evaluate the rapidly expanding research about IBS, a series of systematic reviews were performed. Standard criteria for systematic reviews were met, including comprehensive literature searching, use of prespeci* ed study selection criteria, and use of a standardized and transparent process to extract and analyze data from studies. Evidence-based statements were developed from these data by the entire ACG IBS Task Force. Recommendations were graded using a formalized system that quanti* es the strength of evidence. Each recommendation was classi* ed as strong (grade 1) or weak (grade 2) and the strength of evidence classi* ed as strong (level A), moderate (level B), or weak (level C). Recommendations in this position statement may be crossreferenced with the supporting evidence in the accompanying article, “ An Evidenced Based Review on the Management of Irritable Bowel Syndrome ” .

Intestinal microbiota in functional bowel disorders: a Rome foundation report

It is increasingly perceived that gut host–microbial interactions are important elements in the pathogenesis of functional gastrointestinal disorders (FGID). The most convincing evidence to date is the finding that functional dyspepsia and irritable bowel syndrome (IBS) may develop in predisposed individuals following a bout of infectious gastroenteritis. There has been a great deal of interest in the potential clinical and therapeutic implications of small intestinal bacterial overgrowth in IBS. However, this theory has generated much debate because the evidence is largely based on breath tests which have not been validated. The introduction of culture-independent molecular techniques provides a major advancement in our understanding of the microbial community in FGID. Results from 16S rRNA-based microbiota profiling approaches demonstrate both quantitative and qualitative changes of mucosal and faecal gut microbiota, particularly in IBS. Investigators are also starting to measure host–microbial interactions in IBS. The current working hypothesis is that abnormal microbiota activate mucosal innate immune responses which increase epithelial permeability, activate nociceptive sensory pathways and dysregulate the enteric nervous system. While we await important insights in this field, the microbiota is already a therapeutic target. Existing controlled trials of dietary manipulation, prebiotics, probiotics, synbiotics and non-absorbable antibiotics are promising, although most are limited by suboptimal design and small sample size. In this article, the authors provide a critical review of current hypotheses regarding the pathogenetic involvement of microbiota in FGID and evaluate the results of microbiota-directed interventions. The authors also provide clinical guidance on modulation of gut microbiota in IBS.

Design of treatment trials for functional gastrointestinal disorders.

This article summarizes recent progress and regulatory guidance on design of trials to assess the efficacy of new therapies for functional gastrointestinal disorders (FGIDs). The double-masked, placebo-controlled, parallel-group design remains the accepted standard for evaluating treatment efficacy. A control group is essential, and a detailed description of the randomization process and concealed allocation method must be included in the study report. The control will most often be placebo, but for therapeutic procedures and for behavioral treatment trials, respectively, a sham procedure and control intervention with similar expectation of benefit, but lacking the treatment principle, are recommended. Investigators should be aware of, and attempt to minimize, expectancy effects (placebo, nocebo, precebo). The primary analysis should be based on the proportion of patients in each treatment arm who satisfy a treatment responder definition or a prespecified clinically meaningful change in a patient-reported outcome measure. Data analysis should use the intention-to-treat principle. Reporting of results should follow the Consolidated Standards for Reporting Trials guidelines and include secondary outcome measures to support or explain the primary outcome and an analysis of harms data. Trials should be registered in a public location before initiation and results should be published regardless of outcome.This document summarizes recent progress and regulatory guidance on design of trials to assess efficacy of new therapies for functional gastrointestinal disorders (FGIDs). The double-masked, placebo controlled parallel-group design remains the accepted standard for evaluating treatment efficacy. A control group is essential, and a detailed description of the randomization process and concealed allocation method must be included in the study report. The control will most often be placebo, but for therapeutic procedures and for behavioral treatment trials, respectively a sham procedure and control intervention with similar expectation of benefit but lacking the treatment principle are recommended. Investigators should be aware of and attempt to minimize expectancy effects (placebo, nocebo, precebo). The primary analysis should be based on the proportion of patients in each treatment arm who satisfy a treatment responder definition, or a prespecified clinically meaningful change in a patient-reported outcome measure. Data analysis should use the intention-to-treat principle. Reporting of results should follow the Consolidated Standards for Reporting Trials guidelines and include secondary outcome measures to support or explain the primary outcome and an analysis of harms data. Trials should be registered in a public location prior to initiation, and results should be published regardless of outcome.

Effect of fibre, antispasmodics, and peppermint oil in the treatment of irritable bowel syndrome: systematic review and meta-analysis.

Objective To determine the effect of fibre, antispasmodics, and peppermint oil in the treatment of irritable bowel syndrome. Design Systematic review and meta-analysis of randomised controlled trials. Data sources Medline, Embase, and the Cochrane controlled trials register up to April 2008. Review methods Randomised controlled trials comparing fibre, antispasmodics, and peppermint oil with placebo or no treatment in adults with irritable bowel syndrome were eligible for inclusion. The minimum duration of therapy considered was one week, and studies had to report either a global assessment of cure or improvement in symptoms, or cure of or improvement in abdominal pain, after treatment. A random effects model was used to pool data on symptoms, and the effect of therapy compared with placebo or no treatment was reported as the relative risk (95% confidence interval) of symptoms persisting. Results 12 studies compared fibre with placebo or no treatment in 591 patients (relative risk of persistent symptoms 0.87, 95% confidence interval 0.76 to 1.00). This effect was limited to ispaghula (0.78, 0.63 to 0.96). Twenty two trials compared antispasmodics with placebo in 1778 patients (0.68, 0.57 to 0.81). Various antispasmodics were studied, but otilonium (four trials, 435 patients, relative risk of persistent symptoms 0.55, 0.31 to 0.97) and hyoscine (three trials, 426 patients, 0.63, 0.51 to 0.78) showed consistent evidence of efficacy. Four trials compared peppermint oil with placebo in 392 patients (0.43, 0.32 to 0.59). Conclusion Fibre, antispasmodics, and peppermint oil were all more effective than placebo in the treatment of irritable bowel syndrome.

Impact of hepatitis C on health related quality of life: a systematic review and quantitative assessment.

Hepatitis C virus (HCV) diminishes health related quality of life (HRQOL), and it is now common to measure HRQOL in clinical trials. We sought to summarize the HRQOL data in HCV, and to establish the minimally clinically important difference (MCID) in HRQOL scores in HCV. We performed a systematic review to identify relevant studies, and converted HRQOL data from each study into clinically interpretable statistics. An expert panel used a modified Delphi technique to estimate the MCID in HCV. We found that patients with HCV scored lower than controls across all scales of the SF‐36. Patients achieving sustained virological response (SVR) scored higher across all scales versus patients without SVR, especially in the physical health domains. HRQOL differences did not correspond with differences in liver histology or ALT levels. Based upon the published data, the expert panel concluded that the SF‐36 vitality scale was most relevant in patients with HCV, and generated a mean MCID of 4.2 points on this scale. In conclusion, patients with HCV have a clinically significant decrement in HRQOL versus controls, and physical HRQOL improves in patients achieving SVR but not in those without SVR. The data further suggest that traditional outcomes fail to capture the full spectrum of illness related to chronic HCV. A difference of 4.2 points on the SF‐36 vitality scale can be used as an estimate of the MCID in HCV, and this value may be used as the basis for power calculations in clinical trials evaluating HRQOL. Supplementary material for this article can be found on the HEPATOLOGY website (http://www.interscience.wiley.com/jpages/0270‐9139/suppmat/index.html). (HEPATOLOGY 2005;41:790–800.)

Efficacy of Prebiotics, Probiotics, and Synbiotics in Irritable Bowel Syndrome and Chronic Idiopathic Constipation: Systematic Review and Meta-analysis

OBJECTIVES:Irritable bowel syndrome (IBS) and chronic idiopathic constipation (CIC) are functional bowel disorders. Evidence suggests that disturbance in the gastrointestinal microbiota may be implicated in both conditions. We performed a systematic review and meta-analysis to examine the efficacy of prebiotics, probiotics, and synbiotics in IBS and CIC.METHODS:MEDLINE, EMBASE, and the Cochrane Controlled Trials Register were searched (up to December 2013). Randomized controlled trials (RCTs) recruiting adults with IBS or CIC, which compared prebiotics, probiotics, or synbiotics with placebo or no therapy, were eligible. Dichotomous symptom data were pooled to obtain a relative risk (RR) of remaining symptomatic after therapy, with a 95% confidence interval (CI). Continuous data were pooled using a standardized or weighted mean difference with a 95% CI.RESULTS:The search strategy identified 3,216 citations. Forty-three RCTs were eligible for inclusion. The RR of IBS symptoms persisting with probiotics vs. placebo was 0.79 (95% CI 0.70–0.89). Probiotics had beneficial effects on global IBS, abdominal pain, bloating, and flatulence scores. Data for prebiotics and synbiotics in IBS were sparse. Probiotics appeared to have beneficial effects in CIC (mean increase in number of stools per week=1.49; 95% CI=1.02–1.96), but there were only two RCTs. Synbiotics also appeared beneficial (RR of failure to respond to therapy=0.78; 95% CI 0.67–0.92). Again, trials for prebiotics were few in number, and no definite conclusions could be drawn.CONCLUSIONS: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.

American College of Gastroenterology monograph on the management of irritable bowel syndrome and chronic idiopathic constipation.

Irritable bowel syndrome (IBS) and chronic idiopathic constipation ((CIC) also referred to as functional constipation) are two of the most common functional gastrointestinal disorders worldwide. IBS is a global problem, with anywhere from 5 to 15 % of the general population experiencing symptoms that would satisfy a defi nition of IBS ( 1,2 ). In a systematic review on the global prevalence of IBS, Lovell and Ford ( 1 ) documented a pooled prevalence of 11 % with all regions of the world suff ering from this disorder at similar rates. Given its prevalence, the frequency of symptoms, and their associated debility for many patients and the fact that IBS typically occurs in younger adulthood, an important period for furthering education, embarking on careers, and / or raising families, the socioeconomic impact of IBS is considerable. Th ese indirect medical costs are frequently compounded by the direct medical costs related to additional medical tests and the use of various medical and nonmedical remedies that may have limited impact. CIC is equally common; in another systematic review, Suares and Ford ( 3 ) reported a pooled prevalence of 14 % , and also noted that constipation was more common in females, in older subjects, and those of lower socioeconomic status ( 3 ). Chronic constipation has also been linked to impaired quality of life ( 4 ), most notably among the elderly ( 5 ). Neither IBS nor CIC are associated with abnormal radiologic or endoscopic abnormalities, nor are they associated with a reliable biomarker; diagnosis currently rests entirely, therefore, on clinical grounds. Although a number of clinical defi nitions of both IBS and CIC have been proposed, the criteria developed through the Rome process, currently in its third iteration, have been those most widely employed in clinical trials and, therefore, most relevant to any review of the literature on the management of these disorders. According to Rome III, IBS is defi ned on the basis of the presence of:

Small Intestinal Bacterial Overgrowth in Irritable Bowel Syndrome: Systematic Review and Meta-analysis

BACKGROUND & AIMS Small intestinal bacterial overgrowth (SIBO) has been proposed as an etiologic factor in irritable bowel syndrome (IBS), but evidence is conflicting. We conducted a systematic review and meta-analysis of the prevalence of SIBO in IBS. METHODS MEDLINE and EMBASE were searched up to November 2008. Case series and case-control studies applying diagnostic tests for SIBO in unselected adults meeting diagnostic criteria for IBS were eligible. Prevalence of a positive test for SIBO was extracted and pooled for all studies, and compared between cases and controls using an odds ratio and 95% confidence interval (CI). RESULTS Twelve studies were identified containing 1921 subjects meeting criteria for IBS. Pooled prevalence of a positive lactulose or glucose hydrogen breath test was 54% (95% CI, 32%-76%) and 31% (95% CI, 14%-50%), respectively, with statistically significant heterogeneity between study results. Prevalence of a positive jejunal aspirate and culture was 4% (95% CI, 2%-9%). The pooled odds ratio for any positive test for SIBO in cases compared with healthy asymptomatic controls was 3.45 (95% CI, 0.9-12.7) or 4.7 (95% CI, 1.7-12.95), depending on the criteria used to define a positive test, with statistically significant heterogeneity for both. CONCLUSIONS Prevalence of SIBO in individuals meeting diagnostic criteria for IBS was highest with breath testing. The prevalence in cases with IBS compared with controls varied according to criteria used to define a positive test. The role of testing for SIBO in individuals with suspected IBS remains unclear.

Yield of Diagnostic Tests for Celiac Disease in Individuals With Symptoms Suggestive of Irritable Bowel Syndrome: Systematic Review and Meta-analysis

BACKGROUND Individuals with irritable bowel syndrome (IBS) report abdominal pain, bloating, and diarrhea, symptoms similar to those in celiac disease. Studies suggest that the prevalence of celiac disease is increased in individuals with IBS; however, evidence is conflicting, and current guidelines do not always recommend screening for celiac disease in these individuals. METHODS We conducted a systematic review and meta-analysis to estimate prevalence of celiac disease in unselected adults who met diagnostic criteria for IBS. MEDLINE (1950 to May 31, 2008) and EMBASE (1980 to May 31, 2008) were searched. Case series and case-control studies that used serologic tests for celiac disease were eligible for inclusion. Prevalence of positive serologic indications of celiac disease and biopsy-proved celiac disease were extracted and pooled for all studies and were compared between cases and controls using an odds ratio and 95% confidence interval. RESULTS Fourteen studies were identified comprising 4204 individuals, of whom 2278 (54%) met diagnostic criteria for IBS. Pooled prevalence of positive IgA-class antigliadin antibodies, either positive endomysial antibodies or tissue transglutaminase, and biopsy-proved celiac disease were 4.0% (95% confidence interval, 1.7-7.2), 1.63% (0.7-3.0), and 4.1% (1.9-7.0), respectively. Pooled odds ratios (95% confidence intervals) for positive IgA-class antigliadin antibodies, either positive endomysial antibodies or tissue transglutaminase, and biopsy-proved celiac disease in cases meeting diagnostic criteria for IBS compared with controls without IBS were 3.40 (1.62-7.13), 2.94 (1.36-6.35), and 4.34 (1.78-10.6). CONCLUSION Prevalence of biopsy-proved celiac disease in cases meeting diagnostic criteria for IBS was more than 4-fold that in controls without IBS.

Effect of Antidepressants and Psychological Therapies, Including Hypnotherapy, in Irritable Bowel Syndrome: Systematic Review and Meta-Analysis

OBJECTIVES:Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disorder. Evidence relating to the treatment of this condition with antidepressants and psychological therapies continues to accumulate.METHODS:We performed an updated systematic review and meta-analysis of randomized controlled trials (RCTs). MEDLINE, EMBASE, and the Cochrane Controlled Trials Register were searched (up to December 2013). Trials recruiting adults with IBS, which compared antidepressants with placebo, or psychological therapies with control therapy or “usual management,” were eligible. Dichotomous symptom data were pooled to obtain a relative risk (RR) of remaining symptomatic after therapy, with a 95% confidence interval (CI).RESULTS:The search strategy identified 3,788 citations. Forty-eight RCTs were eligible for inclusion: thirty-one compared psychological therapies with control therapy or “usual management,” sixteen compared antidepressants with placebo, and one compared both psychological therapy and antidepressants with placebo. Ten of the trials of psychological therapies, and four of the RCTs of antidepressants, had been published since our previous meta-analysis. The RR of IBS symptom not improving with antidepressants vs. placebo was 0.67 (95% CI=0.58–0.77), with similar treatment effects for both tricyclic antidepressants and selective serotonin reuptake inhibitors. The RR of symptoms not improving with psychological therapies was 0.68 (95% CI=0.61–0.76). Cognitive behavioral therapy, hypnotherapy, multicomponent psychological therapy, and dynamic psychotherapy were all beneficial.CONCLUSIONS: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.