Physician's Weekly Article - New Guidelines for Managing IBS

       For the first time since 2002, the American College of Gastroenterology has updated guidelines for the management of IBS. Recommendations highlight recent changes in the clinical landscape and emerging evidence on the benefits and risks of new therapies.

      IBS is one of the most commonly seen problems by primary care physicians and clinical gastroenterologists, affecting 10% to 15% of the general population. According to the American College of Gastroenterology (ACG), the disease is characterized by abdominal pain or discomfort that is associated with altered bowel function, but structural and biochemical abnormalities are absent. “IBS is a prevalent and expensive condition that is largely misunderstood by providers,” says William D. Chey, MD. “It greatly impairs quality of life. When compared with the general population, those with IBS make more visits to their physicians, undergo more diagnostic tests, and are prescribed more medications. They also miss more workdays and have lower work productivity, are hospitalized more frequently, and account for greater overall direct and indirect costs.”

      A Necessary Update

      The ACG released guidelines for the management of IBS in 2002 but has since updated these recommendations. Published in a January 2009 supplement of the American Journal of Gastroenterology, the ACG IBS Task Force’s recommendations were developed after conducting a comprehensive review of the latest medical research and expert consensus. “The updated guidelines provide clinicians with a comprehensive and practical set of recommendations for the diagnosis and treatment of IBS,” says Dr. Chey, who was a member of the ACG IBS Task Force. “New evidence has also emerged on the benefits and risks of drugs and other therapies used for IBS. The development of new drugs and the evidence of their efficacy were also assessed in the updated guidelines.”

      Making the Diagnosis

      The updated ACG guidelines provide a revised symptom-based definition for IBS. The condition is now defined by “abdominal pain or discomfort that occurs in association with altered bowel habits over a period of at least 3 months.” Dr. Chey says that individual symptoms have limited accuracy for diagnosing IBS. “As such, the disorder should be considered as a symptom complex. However, the task force continues to recommend that providers screen for selected ‘alarm features,’ including anemia, weight loss, and a family history of colorectal cancer, inflammatory bowel disease, or celiac sprue.” When present, alarm features identify a group of patients who should be evaluated to exclude an organic cause for their symptoms. When absent, clinicians can be reassured of a correct IBS diagnosis.

      The ACG IBS Task Force also concluded that there is a low likelihood of uncovering organic diseases such as colon cancer, inflammatory bowel disease, and thyroid disease in patients with typical IBS symptoms and no alarm features. “Routine testing with comprehensive evaluations should not be performed in patients with typical IBS symptoms and no alarm features,” says Dr. Chey (Table 1). The pretest probability of celiac disease, lactose maldigestion, and microscopic colitis was found to be elevated in patients with IBS symptoms. Because of this, the task force recommended serological screening for celiac disease in patients with diarrhea-predominant IBS and mixed IBS. The task force also suggested that providers considerbreath testing for lactose maldigestion when questions remain despite dietary exclusion and random colon biopsies to exclude microscopic colitis when IBSD patients undergo colonoscopy.

      New Treatment Options Available

      Treatments for IBS have been generally directed towards predominant symptoms. Many therapies— including OTC drugs and supplements as well as prescription medications—have become available to improve individual IBS symptoms. However, only a few therapies have been shown to be of benefit for global symptoms of IBS (Table 2). “OTC therapies such as psyllium, fiber, certain antispasmodics, and peppermint oil appear to be effective in IBS, but the quality of current evidence is poor for these agents,” Dr. Chey says. “Additionally, some probiotics and anti-diarrheal drugs may also be of benefit, but more data are needed.

      “With regard to prescription drugs,” Dr. Chey continues, “5HT₃ antagonists have demonstrated good efficacy in IBS patients with diarrhea, but careful patient selection is required because of potentially serious side effects. Tricyclic antidepressants and selective serotonin reuptake inhibitors have been shown to be effective, but more high-quality evidence is needed. Another approach is to use non-absorbable antibiotics, particularly in diarrhea-predominant IBS. There is now solid evidence to support short-term benefits in IBS patients. For people with constipation-predominant IBS, lubiprostone—a selective C2 chloride channel activator—appears to be efficacious based on high-quality evidence.” Dr. Chey adds that psychological therapies may provide benefits, but the quality of evidence is variable. Furthermore, routine use of food allergy testing and exclusion diets is not recommended due to a paucity of high-quality evidence.

      A Bright Future

      “Our knowledge of the pathogenesis of IBS is expanding,” says Dr. Chey. “This has led to the identification of novel therapies for the disease. We have new classes of agents in development and we’re also assessing the effect of existing classes of therapies on IBS. While we await data on these potential options, clinicians should understand that we do have good treatment options available now. By diagnosing the condition accurately and using available medications and therapies, IBS can be managed effectively in most patients.”

      William D. Chey, MD, has disclosed to Physician’s Weekly that he has received consulting fees from AGI, Novartis, Procter & Gamble, Salix, Takeda, and Prometheus, and lecture fees from Novartis, Procter & Gamble, Salix, Takeda, and Prometheus.