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Volume 3, Supplement 2, 2003

Volume 3, Supplement 2, 2003

Table of Contents

Impact of Irritable Bowel Syndrome: Prevalence and Effect on Health-Related Quality of Life
The prevalence of a disease and its effect on health-related quality of life (HRQOL) are important measures of its burden on society. The prevalence of irritable bowel syndrome (IBS) symptoms in the U.S. general population is approximately 10%, with lower estimates of prevalence if IBS is defined according to the more restrictive ROME II criteria. In population-based studies, there are no large differences in the prevalence of IBS symptoms between men and women or among the three major symptom subtypes of IBS (diarrhea- or constipation-predominant or alternating). However, the majority of persons with IBS-like symptoms do not seek care for these symptoms and, in those who do seek care, there is a 2-to-1 female-to-male predominance. HRQOL is an important measure that should be considered in the overall assessment of a largely subjective, nonfatal disease such as IBS. Studies that have measured HRQOL in IBS used generic instruments, mostly the 36-Item Short Form Health Survey, and few have used IBS-specific instruments. In a systematic review of the literature, there is strong evidence that persons with moderate to severe IBS who seek care for their symptoms (consulters) show decreased HRQOL. The impact of IBS on HRQOL in nonconsulters is less clear. Finally, a therapeutic response in IBS-related symptoms corresponds with an improvement in HRQOL. [Rev Gastroenterol Disord. 2003;3(suppl 2):S3–S11]
Diagnosing Irritable Bowel Syndrome
It is often possible to positively diagnose irritable bowel syndrome (IBS) based on a combination of multiple symptoms and their chronic nature. Both the Manning criteria and the ROME 1999 Consensus Working Party Diagnostic Criteria help in diagnosing IBS. It is important that, during the first visit, possible contributing factors, such as associated psychosocial stress or a history of mental, physical, or sexual abuse, are considered as part of the patient evaluation. Patients need to receive a clear explanation of the possible causes of symptoms, the benign nature of IBS, and the low likelihood of serious underlying disease. An interactive, positive physician– patient relationship has a beneficial effect on the course of IBS and may be associated with a decreased need for future health care visits. [Rev Gastroenterol Disord. 2003;3(suppl 2):S12–S17]
Traditional Therapies for Irritable Bowel Syndrome: An Evidence-Based Appraisal
Irritable bowel syndrome (IBS) is a common chronic disease that adversely effects quality of life and is associated with substantial direct and indirect health care costs. It is defined by a constellation of symptoms in conjunction with an alteration in bowel function and defecation, and its underlying pathophysiological basis remains unknown. Numerous therapies are available, but many relieve only one symptom of the syndrome, and their effectiveness has not been demonstrated with adequate evidence from high-quality studies. This article reviews the criteria for appropriate design of any treatment study as well as those criteria specific to studies of treatment for functional gastrointestinal diseases. Using these criteria, the author evaluates the published investigations of “traditional" IBS therapies (antidepressants, bulking agents/fiber, antispasmodics, antidiarrheals) and “alternative" IBS therapies (Chinese herbal supplements, peppermint oil, behavioral therapies). Based on this evaluation, the author concludes that the available evidence does not support the effectiveness of any of these treatments and, therefore, none of these treatments can be reliably recommended. [Rev Gastroenterol Disord. 2003;3(suppl 2):S18–S24]
Serotonin and its Implication for the Management of Irritable Bowel Syndrome
Our understanding of the enteric nervous system (ENS) has evolved from the “classical" view, in which the brain controls all enteric behavior, to the current view, which holds that enteric innervation is one of local control within the bowel, modified by a bidirectional “dialogue" with the brain. The ENS independently controls enteric reflexes through intrinsic primary afferent neurons, which monitor intraluminal conditions. This monitoring is accomplished through the use of enteroendocrine cells in the mucosa, the best known of which are the serotonin-containing enterochromaffin cells. This article describes the roles that serotonin, specific serotonin-receptor subtypes, and the serotonin reuptake transporter play in the ENS and in the communication between the ENS and central nervous system. The way in which these findings have implicated serotonin in irritable bowel syndrome is discussed. [Rev Gastroenterol Disord. 2003;3(suppl 2):S25–S34]
Tegaserod and Other Serotonergic Agents: What Is the Evidence?
Through effects on gastrointestinal motor and secretory function as well as visceral sensation, serotonin (5-HT) plays a key role in the pathogenesis of irritable bowel syndrome (IBS). In particular, 5-HT3 and 5-HT4 receptors appear to be very important in IBS. This article critically appraises the evidence supporting the use of the 5-HT3 receptor antagonist alosetron in the treatment of women with diarrhea-predominant IBS. The safety profile and restricteduse program for alosetron is also reviewed. This discussion is followed by a comprehensive review of the efficacy and safety data in support of tegaserod for women with constipation-predominant IBS. [Rev Gastroenterol Disord. 2003;3(suppl 2):S35–S40]