This past week, on August 5, the American College of Gastroenterology Task Force on Functional Bowel Disorders, publicly released the 2014 ACG evidence-based systematic review on the management of irritable bowel syndrome (IBS) and chronic idiopathic constipation (CIC), also known as functional constipation. The last such review was in 2009. The updated review was issued as a monograph supplement to the August 2014 issue of The American Journal of Gastroenterology. The full 25 page text in PDF format is accessible at the above link.
The task force included eight leading expert clinicians and researchers of functional gastrointestinal disorders from various academic research centers in the United States and Canada. The chair was Eamonn Quigley, MD, FRCP, FACG of Houston, Methodist Hospital and Weill Cornell Medical College. Other members were Brian Lacy, MD, PhD, FACG, of Dartmouth Hitchcock Medical Center, Anthony Lembo, MD of Harvard Medical School and Beth Israel Deaconess Medical Center, Paul Moayyedi, BSc, MB, ChB, PhD, MPH, FRCP (London), FRCPC, FACG of McMaster University Medical Centre, Yuri Saito, MD, MPH of the Mayo Clinic, Rochester, Lawrence Schiller, MD, FACG of Baylor University Medical Center, Edy Soffer, MD, FACG of the Keck School of Medicine, University of Southern California, and Brennan Spiegel, MD, MSHS of the UCLA School of Medicine. According to a press release sent directly to IBS Impact by the ACG media contact, “Dr. Moayeddi conducted the systematic reviews with support from Alexander C. Ford, MD, ChB, MD [sic], FRCP, and carried out the technical analyses of the data independent of the Task Force.” (page 2)
The task force sought to systematically examine and evaluate available research literature on a wide variety of conventional and complementary treatment interventions, both existing and relatively new, that are commonly used for IBS. These included but were not restricted to diet, probiotics, the non-absorbable antibiotic rifaximin (brand name Xifaxan), antidepressants, antispasmodics, peppermint oil, bulking agents and laxatives, including loperamide (Immodium), the 5-HT3 receptor antagonist alosetron (Lotronex for severe IBS-D, available under FDA-restricted distribution only because of past serious safety concerns), the 5-HT4 serotonin receptor agonist tegaserod (Zelnorm for IBS-C, no longer available in the United States because of past serious safety concerns), the chloride channel activator lubiprostone (Amitiza), psychological therapies such as hypnotherapy and biofeedback, herbal preparations, and acupuncture. The task force used preset criteria in selecting reliable studies to review and used meta-analyses when appropriate. The quality of evidence for the effectiveness of each type of treatment was graded, again using standard scales. The full report also notes instances of possible bias or other study limitations. The task force’s revised recommendations are based on the quality of evidence and other considerations like risks and costs and possible patient preferences.
Some of the notable conclusions of the task force follow:
Elimination diets may be helpful to some people with IBS, but the overall reliability of available evidence is “very low,”(page 56 of monograph, page 5 of PDF). The low-FODMAP approach specifically is considered to “show promise” but in need of more research to determine more precisely how or why it may work. (page 58 of monograph, page 7 of PDF.) For those with IBS whom increasing fiber intake helps, the evidence is stronger for psyllium (soluble fiber) than for bran (insoluble fiber). Probiotics can moderately improve global symptoms, bloating and flatulence in IBS for some people, but relatively few strains have been specifically studied for IBS, and it is not possible at this time to target specific individuals they may help or specific strains to recommend. Prebiotics and synbiotics do not have sufficient evidence of effectiveness. Rifaximin has moderate evidence of effectiveness for diarrhea-predominant IBS, but the task force expresses concern about potential long-term antibiotic resistance, uncertainty about long-term effectiveness, and the relatively high expense of this treatment to patients. Linaclotide (Linzess in the United States; Constella in Europe) and lubriprostone (Amitiza) garner strong recommendations from the task force for use in constipation-predominant IBS. This is particularly of interest, since the vast majority of treatment types reviewed, even many long considered to be traditional, established approaches to IBS, have received “weak” recommendation (page 56 of monograph, page 5 of PDF). Also, the review concludes that there is increased evidence than in previous years to support antidepressants and psychological therapies as effective for IBS, however, the report notes that antidepressants tend to have various side effects that some people with IBS may not be willing or able to tolerate, and the dearth of mental health professionals knowledgeable about and experienced in psychological therapies for IBS is a barrier to widespread use of psychological treatments.
The task force emphasizes that although IBS research is quickly increasing and evolving, the vast majority of available treatments continue to be aimed at an individual’s predominant Rome criteria symptom, not on the global symptoms of IBS as a whole, and only a small subset of people with IBS tend to be helped by any given intervention. It is important to work with one’s personal physician and other health care providers to determine the appropriate management options for one’s own situation and preferences.
IBS Impact appreciates the work of the task force and ACG’s willingness to make this review readily available to the functional GI community, professionals and affected individuals alike. Although ACG’s recommendations for IBS management are not drastically changed from five years ago when the last review was published, it is clear that the field is moving incrementally forward. Periodic peer review is important to the scientific process and future advances, and the availability of this document provides a comprehensive summary and guidance to professionals providing health care to people with IBS and to interested people with IBS in the most current standards of care for IBS in the United States. When so many people with IBS, families and professionals continue to receive outdated or inaccurate information about basic aspects of IBS, an evidence-based document is an important tool in education and management of IBS.