Sparse evidence to support efficacy of traditional IBS treatments

Last Updated: 2020-01-08

By Will Boggs MD

NEW YORK (Reuters Health) - Traditional treatments for irritable bowel syndrome (IBS) are supported only by limited data from trials with significant risk of bias, according to a systematic review and network meta-analysis.

"The management of the individual patient is nuanced, but the results of this study should allow physicians to understand which treatments are more likely to be effective for global symptoms or abdominal pain," Dr. Alexander C. Ford from Leeds Gastroenterology Institute, St. James's University Hospital, Leeds, UK, told Reuters Health by email.

Several new drugs have been approved to target specific stool patterns associated with IBS, but these drugs tend to be expensive or their availability is limited, and some have been withdrawn or had their use restricted because of safety concerns.

As a result, many physicians in clinical practice rely on other, so-called traditional treatments as first-line or second-line therapies for patients with IBS. There is little information to guide the choice among these treatments.

Dr. Ford and colleagues undertook a network meta-analysis to compare and rank the efficacy of soluble fiber, antispasmodic drugs, and gut-brain neural modulators (tricyclic antidepressants (TCAs), selective serotonin-reuptake inhibitors (SSRIs), and alpha-2-delta calcium channel subunit ligands) for treatment of IBS.

Only 13 of the 51 studies included in the network meta-analysis were deemed to be at low risk of bias.

Peppermint oil, TCAs, and antispasmodic drugs significantly outperformed placebo for providing an improvement in global IBS symptoms at 4-12 weeks of treatment, with peppermint oil ranking first in the network meta-analysis, according to the online report in Lancet Gastroenterology and Hepatology.

For abdominal pain, TCAs, antispasmodic drugs, and peppermint oil (in that order) were significantly more efficacious than placebo.

For both of these endpoints, there were no significant differences in efficacy between treatments through indirect comparisons across studies. The network meta-analysis rankings were based on P-scores (which, in turn, are based solely on the point estimates and standard errors of the network estimates and reflect the extent of certainty that one treatment is better according to any given endpoint than another treatment).

Ispaghula husk (a soluble fiber) was least likely and TCAs were most likely to be associated with adverse events, but none of the therapies were more likely than placebo to lead to withdrawal from the study due to adverse events.

"Although this information might assist clinicians and patients with IBS to decide which therapy might be appropriate, we would like to emphasize that the quality of the evidence in our study was low because of the high risk of bias of trials included in our analysis, and because the endpoints used to judge treatment efficacy were less stringent than those used in RCTs of newer drugs," the authors note.

Dr. Hans Tornblom from Sahlgrenska Academy, University of Gothenburg, Sweden, who wrote an editorial related to this report, told Reuters Health by email, "This study does not change how we should look upon our current guidelines, rather emphasizes the need to understand the multidimensional clinical profile that is presented by many IBS patients. There is no point in using a mediocre medication aiming at a specific symptom if the patient agenda primarily is something else, such as fear of another disease or disorder."

"These medications are useful in specific situations," he said. "Understand the evidence base by reading up on IBS. These patients are most often in need of tailored treatments where a medication quite often is not the most important part."

"Do not forget the importance and positive effects of a good patient-doctor interaction in IBS," Dr. Tornblom added. "Make the diagnosis (do not get confused by the intensity of symptoms if alarm features are lacking), understand the patient's agenda for seeing you, do not make things difficult by delaying the diagnosis by waiting for test result before mentioning it as the most possible diagnosis, educate the patient in basic mechanisms underlying IBS (we know a lot!), and get to know the patient before deciding upon medications in order to improve the chances of having a good response in a patient that knows what to expect from the treatment (pain relief, improvement in bowel function, reduced global symptom burden, etc.)."

SOURCE: http://bit.ly/2t2t8zh and http://bit.ly/2NndvJR Lancet Gastroenterology and Hepatology, online December 16, 2019.