Bloating, Abdominal Pain Are ‘Driving Factors’ in Global IBS-D Symptom Scores

Rifaximin (Xifaxan) is approved for the treatment of adults with irritable bowel syndrome plus diarrhea (IBS-D) and has demonstrated efficacy versus placebo for the improvement of abdominal and bowel symptoms, including fecal urgency and stool consistency.

A post-hoc analysis of two phase III trials was conducted to determine which of those symptoms are the real driving factors for patients’ global IBS symptom scores. The findings were presented at the American College of Gastroenterology annual meeting.

In this exclusive MedPage Today video, Kyle Staller, MD, MPH, director of the Gastrointestinal Motility Laboratory at Massachusetts General Hospital in Boston, discusses the study.

Following is a transcript of his remarks:

I’m Dr. Kyle Staller. I’m the director of the GI Motility Laboratory at Massachusetts General Hospital and assistant professor of medicine at Harvard Medical School. And today I’m talking about our work, looking at some post-hoc analyses from two phase III trials of rifaximin in irritable bowel syndrome with diarrhea, or IBS-D.

And essentially, we’re really interested to see what are the real driving symptoms for these patients in IBS. We know IBS is defined by abdominal pain, and at this point, discomfort in association with the change in bowel habits. And for IBS-D, that’s loose stools. And so we wanted to look at within the various types of symptoms that are involved in IBS, because there’s more than that — there’s bloating, there’s pain, there’s loose stools — what are the real driving factors for patients’ global IBS symptoms score? And so this is really looking at two phase III trials that were really part of getting rifaximin approved for IBS-D by the FDA.

And basically we looked at the correlation of these symptoms with each other in addition to global IBS wellbeing over the time of this particular trial. And so while the trial really established the efficacy of rifaximin in this patient population, our interest is to learn more about IBS itself.

And what we found is that when we looked at the correlation of these symptoms, the symptoms that correlated most with each other were abdominal pain and bloating. And interestingly, those same two symptoms highly correlated with global IBS score. So as that global IBS score changed, so too did bloating and pain, which suggests that bloating and pain are really the drivers of overall symptoms in IBS.

Whereas if we looked at stool consistency, which is really our tendency in a lot of practices to really focus on stool consistency and target stool consistency with our interventions, stool consistency was only moderately correlated with global IBS wellbeing or global IBS symptoms.

And so what we found is that, really, it’s that bloating and pain are the real drivers of symptoms in this patient population. And I think that that speaks to the fact that bloating and pain may be the most important targets when we’re considering therapeutic interventions.