Spotlight on IBS treatments

While there is no cure for irritable bowel syndrome (IBS), recent research found that a range of treatments may effectively control symptoms.

First, a study found that patients with IBS are willing to take medication risks and would spend a fair amount of money per month to resolve their pain. Researchers at one U.S. tertiary referral hospital surveyed 215 adult patients (mean age, 57 years; 82% women) who had a gastroenterology office visit between 2015 and 2016 and met Rome IV criteria for IBS. Participants had an average duration of IBS symptoms of 17.7 years. A standard gamble evaluated their willingness to take medication risks, and a willingness-to-pay set of questions quantified maximal spending on a hypothetical medication to treat IBS. Results were published online on April 11 by Clinical Gastroenterology and Hepatology.

Unpredictability of symptoms was the most bothersome feature of IBS (59.6% of patients), followed by diarrhea (39.3%) and abdominal pain (30.4%). Patients whose predominant symptom was severe diarrhea reported accepting a mean 10.2%±15.7% risk of sudden death for a 99% chance of cure, whereas those with IBS and pain catastrophization did not have an increased likelihood of taking medication risks. Participants reported that they would be willing to pay between average amounts of $73 per month (if annual income was below $75,000) and $197 per month (if annual income was above $75,000) for a medication that would resolve their IBS pain. Among other limitations, participants were predominantly white and from the New England region, the study authors noted. “IBS patients are willing to consider taking substantial risks to improve their overall symptom burden,” they concluded. “Clinicians should be mindful of this when addressing patients with IBS, and a multidimensional approach appears most logical for patients with IBS, weighing the risks and benefits on different preference-based treatment approaches.”

One potential treatment approach for IBS is probiotic therapy. In one industry-funded study, published online on April 8 by The Lancet Gastroenterology & Hepatology, researchers at 20 sites in Germany performed a double-blind, placebo-controlled trial of nonviable, heat-inactivated Bifidobacterium bifidum MIMBb75, a probiotic strain that has been shown to be effective in treating IBS and its symptoms. A total of 443 patients with IBS according to Rome III criteria were randomly assigned to receive oral capsules of the bacteria (n=221) or placebo (n=222) once a day for eight weeks. The primary composite end point was the combination of at least 30% improvement of abdominal pain and adequate relief of overall IBS symptoms in at least four of eight weeks during treatment. This end point was reached by 74 (34%) patients in the B. bifidum group, compared to 43 (19%) in the placebo group (risk ratio, 1.7; 95% CI, 1.3 to 2.4; P=0.0007). There were no serious adverse events, and tolerability was rated as very good or good by 91% of patients in the B. bifidum group and 86% of those in the placebo group.

By heat-inactivating the bacteria, which is found in the healthy human colon, the study authors “did not administer a probiotic but a bacterial therapy,” although the mechanism of action of B. bifidum in IBS remains unknown, an accompanying comment noted. In addition, bacterial therapies do not appear to permanently change a patient's microbiome, and the benefits appear to rely on repeat administration, the comment said. “The absence of fundamental knowledge in terms of how bacterial therapy alters mechanisms in IBS continues to hamper improvements in treatment, limiting any success to short-term symptom control rather than the true goal, reversal of disease,” the editorialists wrote.

Next, a systematic review and network meta-analysis, published April 10 by Gut, looked at 41 randomized controlled trials of 4,072 participants to compare the efficacy of different psychological therapies to treat adults with IBS. Of the active interventions that were superior to a control, self-administered or minimal-contact cognitive behavioral therapy (CBT), face-to-face CBT, and gut-directed hypnotherapy had the most evidence for efficacy (pooled relative risk, 0.61 [95% CI, 0.45 to 0.83]; 0.62 [95% CI, 0.48 to 0.80]; and 0.67 [95% CI, 0.49 to 0.91], respectively); however, all trials were at high risk of bias. None of the therapies were superior to another. The therapies with the best evidence for longer-term efficacy were self-administered or minimal-contact CBT, stress management, CBT via the telephone, CBT via the internet, gut-directed hypnotherapy, and group gut-directed hypnotherapy. CBT via the telephone appeared to be the most beneficial intervention at 12 months.

For the final study, researchers conducted two trials at a gastroenterology outpatient clinic in Sweden to compare the effectiveness of internet-delivered versus face-to-face education for patients with IBS. The three-week educational interventions were identical except for the delivery format. In the first trial, 141 patients were randomly assigned to receive either internet-delivered or face-to-face education from August 2016 through June 2017. In the second trial, 155 patients were allowed to choose either intervention. Patients completed questionnaires before, during, and after education. The primary outcome was the IBS symptom severity scale (IBS-SSS; range, 0 to 500, with higher scores indicating more severe symptoms), and the primary test of noninferiority was the difference in change up to six months after education (noninferiority margin, 40 points). Results were published online on April 11 by Clinical Gastroenterology and Hepatology.

In the primary analysis, patients who received face-to-face education had an average reduction in IBS-SSS score that was 12.2 points more than that of those who received internet education (one-sided 95% CI upper bound, 38.4 points). In the per protocol analysis, patients who received face-to-face education reduced their IBS-SSS score by 14.7 points more than those who received internet education (95% CI upper bound, 35.5 points). While face-to-face education had significantly higher credibility and produced a significantly larger increase in self-rated knowledge, most patients preferred internet-delivered education, which met the noninferiority criteria. “This motivates further dissemination of Internet-delivered education as a way of increasing the availability of education programs in the clinic to help IBS patients to manage their symptoms,” the study authors concluded.