IBS, Chronic Idiopathic Constipation: New Guidelines Issued

Larry Hand

August 06, 2014

New guidelines from the American College of Gastroenterology offer some new approaches to treating irritable bowel syndrome (IBS) and chronic idiopathic constipation (CIC) and shed new light on traditional interventions. The guidelines are presented in an article published in the August issue of the American Journal of Gastroenterology.

Alexander C. Ford, MB ChB, MD, FRCP, from the Leeds Gastroenterology Institute, St James's University Hospital, United Kingdom, and colleagues conducted a systematic review and meta-analysis of randomized clinical trials of several types of interventions for IBS and CIC.

The impetus for publishing a new monograph came from the ACG's Institute for Clinical Research & Education. "The institute looked back over the various guidelines and monographs done in recent years, and the last one on constipation was as far back as 2005, and the last one on [IBS] was in 2009," coauthor Eamonn M.M. Quigley, MD, chief of gastroenterology and hepatology at Houston Methodist Hospital and Weill Cornell Medical College, Houston, Texas, told Medscape Medical News. "It was felt that there had been significant developments in both areas in the interim and that enough data was indicated."

Drug Therapy

"The primary event that is common to both [IBS] and chronic constipation is the emergence of drugs that act only in the [gastrointestinal] tract, those that don't depend on other action," Dr. Quigley said. "They do not have to be absorbed into the bloodstream to be effective in the [gastrointestinal] tract."

The authors give linaclotide (Linzess, Ironwood Pharmaceuticals) a strong recommendation for both IBS and CIC and characterize the quality of evidence as high. They give lubiprostone (Amitza, Takeda Pharmaceuticals) a strong recommendation for IBS and CIC and characterize the quality of evidence as moderate for IBS and high for CIC.

"Both of these [drugs] seem to be effective for both chronic constipation and [IBS]," Dr. Quigley said.

Dietary Influence

Some new information for clinicians, but not for patients, came up during the meta-analysis about diet's relationship with IBS, he said.

"When you stand back and look, there are a number of things that do jump out," he continued. "The first thing is the emergence of diet as a major issue in [IBS]. For patients, this isn't new, because patients have contended for years that certain foods upset them, but we were very dismissive of that. But now there's good evidence that diet is a major factor, probably not of the causation of [IBS], but in the precipitation of attacks."

The authors write that specialized diets may improve symptoms in some individual patients with IBS, but they give them a weak recommendation and characterize the quality of evidence is very low.

Among the new dietary guidance, the authors write, current data show that gluten-free diets and diets low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols "show promise but their precise role(s) in the management of IBS need to be defined."

Regarding the diets low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, Dr. Quigley commented, "There is, I think, now quite good evidence that this diet can help some people. There's enormous lay interest in the gluten-free diet, and there is some evidence — it's controversial — that a gluten-free diet may have a role in [IBS]."

Gut Microbiota

The authors characterize the quality of evidence for prebiotics and synbiotics as very low and give them a weak recommendation for IBS, although they acknowledge that, "Taken as a whole, probiotics improve global symptoms, bloating, and flatulence in IBS."

Regarding probiotics, Dr. Quigley commented, "In this metaanalysis we show that probiotics in general seem to have a beneficiary effect for irritable bowel syndrome."

Tricky Fiber

For both IBS and CIC, fiber is a sticky issue.

"Fiber is the trickiest," Dr. Quigley said. "A person with [IBS] needs to be careful with fiber. Fiber actually makes some people worse. In constipation, the evidence on fiber, believe it or not, is also not great, though the evidence on fiber supplements is good in constipation, and to a lesser extent in [IBS]."

Asked what he would tell patients, he said. "I think for people with chronic constipation, slowly increasing your fiber intake is certainly a worthwhile strategy. For people with [IBS], one needs to be more cautious, because there are problems with bloating, to which these patients are very sensitive."

Other Recommendations

The monograph also contains recommendations on other treatments, including antidepressants, antibiotics, serotonergic agents, psychological therapies, and for CIC, laxatives.

Dr. Quigley summarized those this way: "A lot of the 'traditional' treatments probably do work to some extent, some more than others. A lot of them suffer from the fact that they were developed before the kind of rigor that we expect from controlled clinical trials in the norm, so when you go and do a scientific metaanalysis, you find there's not a lot of evidence to support them."

He continued, "That doesn't mean they don't work, it's just that they have not had high-quality research performed. More recently, some of the more traditional laxatives...have actually been subjected to high-quality research and have been shown to work. I think for constipation we have quite a few alternatives."

This research was supported Forest Laboratories, Ironwood Pharmaceuticals, Nestle Health Science, and Prometheus Laboratories. Six coauthors have reported receiving research support from and/or serving as advisors and/or speakers for several pharmaceutical companies; none of the other coauthors has disclosed any relevant financial interest.

Am J Gastroenterol. 2014;109:S2-S26. Full text


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