New IBS guidelines

The guidelines, issued by the American College of Gastroenterology and published in The American Journal of Gastroenterology, essentially replace a 2002 document.

"The world of IBS is changing quickly because of more therapies and an increased awareness. It is considered a 'real disease,'" said Dr Lawrence Brandt, chairman of the group's IBS task force and chief of gastroenterology at Montefiore Medical Centre in New York City. "A lot of new drugs are being developed, and a lot of work still needs to be done, but there's enough new information since the last time."

"From the practitioner's standpoint, this doesn't change much about practice and there's not that much information that's new, although it is thorough and helpful," said Dr Benjamin D. Havemann, an assistant professor of internal medicine at the Texas A&M Health Science Centre College of Medicine and director of gastroenterology for the Round Rock University Medical Campus of Scott & White Hospital. "It shows what little has transpired [in terms of new treatments] in the last few years. Some of the breakthroughs we had have been withdrawn or are under strict control."

"One powerful piece of information is that extensive work-ups are unhelpful," Havemann said. "It makes sense to me that in the absence of alarm symptoms, the benefit of even basic blood work and other tests is in doubt."

Affects quality of life
An estimated 7% to 10% of people have IBS, which can involve abdominal pain, bloating and other discomfort, including constipation and diarrhoea. IBS affects both quality of life and productivity for millions of people.

Most IBS treatments relieve symptoms rather than resolve the condition itself. The new guidelines encompass existing evidence on conventional treatments for IBS as well as new therapies (probiotics, for example) and alternative therapies (acupuncture and more). In summary, the updated guidelines say:

• Fibre products - including psyllium, anti-spasmodic medications and peppermint oil - may be effective, at least in some people. "The evidence is poor, but some patients say they feel better," Brandt said. He cautioned that fibre should be used carefully in people with narrowed colons.
• More data is needed on probiotics, live microorganisms (usually bacteria) similar to the "good" organisms found normally in the gut. "This is a very hot topic, but an exceedingly complicated subject," Brandt said. Researchers and practitioners need to consider the species of bacteria used, how many species, and dosages.
• Non-absorbable antibiotics - those targeted to the gut only, such as rifaximin (Xifaxan) - also seem to help some people, especially those who have "diarrhoea-predominant IBS." Brandt said that "the data is not great, but some patients swear they're helping them dramatically."
• Tricyclic antidepressants as well as the antidepressants known as selective serotonin reuptake inhibitors (SSRIs) benefit a broad range of people with IBS. This is backed up by quality studies, although with small numbers of participants, and could change as research on larger numbers of people is evaluated. Psychological counselling may also provide some relief.
• >Selective C-2 chloride channel activators, notably lubiprostone (Amitiza), are effective for "constipation-predominant IBS."
• 5HT 3 antagonists such as alosetron (Lotronex) relieve symptoms of diarrhoea, but can cause constipation and colon ischaemia, a restriction of blood flow.
• 5HT 4 agonists, though effective against constipation, are not available in North America because of a heightened risk of cardiovascular problems.
• There is yet to be conclusive evidence on Chinese herbal mixtures, and the mixtures run the risk of causing liver failure and other problems. Differences in the content of compounds and the purity of ingredients complicate evaluation of benefits.
• Similarly, the evidence on acupuncture remains inconclusive.
• There is no evidence at this point that testing for food allergies or following diets that exclude certain foods alleviates IBS symptoms.
• Routine diagnostic testing for IBS is not recommended, although some testing should be performed in certain subgroups of patients.

Though comprehensive, the guidelines were criticised for not explaining what outside funding was used for in the development process. The document does disclose that support was received from Takeda Pharmaceutical Co. and Salix Pharmaceuticals, which make products targeted to IBS.

Dr Mark Ebell, deputy editor of American Family Physician, said he would feel more comfortable if the guidelines had been "very clear about what support was provided and what they needed the support for: paying for literature searches, for staff. … It's common to have support for guidelines. … I think it's generally unintentional, but when we have a relationship, it creates the potential for problems."

Ebell said that Brandt had relationships with pharmaceutical companies. Brandt had a different view. "I don't have any ties to industry that would have any relevance to this publication," he said. "I don't receive money directly from any company. I own no stock and, nor does my family, so this is a totally unbiased thing. I have no conflict of interest whatsoever, and I think that does it."

Anne-Louise B. Oliphant, a spokeswoman for the American College of Gastroenterology, said: "No company was involved in any way in either structuring or completing the meta-analysis that forms the basis for the College's evidence-based recommendations on IBS. Furthermore, no company was in any way involved in deciding who served on the task force or in any of its work." - (Amanda Gardner/HealthDay News)

December 2008