Low-FODMAP diet trumps medication for IBS

In primary care patients with irritable bowel syndrome (IBS), keeping a diet low in fermentable oligo-, di-, and monosaccharides and polyols (FODMAP), as guided by a smartphone app, yields better symptom relief than using a spasmolytic agent, according to a recent trial.

Of the 459 IBS patients enrolled (mean age 41 years, 76 percent women), 217 were randomized to receive the spasmolytic agent otilonium bromide (OB) while 218 were tasked to keep a low-FODMAP diet. At the 8-week follow-up, responder rate was significantly higher in the diet vs OB arm (71 percent vs 61 percent; p=0.03). [Gut 2022;doi:10.1136/gutjnl-2021-325821]

Such a difference became apparent and significant as early as week 4 (62 percent vs 51 percent; p=0.02). Similar findings were obtained from an intention-to-treat analysis.

Logistic regression analysis revealed that women were more than twice as likely to respond to the low-FODMAP diet than men (odds ratio, 2.08, 95 percent confidence interval, 1.08–4.03; p=0.04), while primary stool type did not affect treatment response.

Moreover, scores in the IBS Symptom Severity Scale (IBS-SSS) improved significantly in the diet vs OB group at weeks 4 (change, –88 vs –61 points, respectively; p<0.001) and 8 (change, –97 vs –77 points, respectively; p<0.001). At both weeks, the magnitude of improvement was greater in the diet group (p=0.004 and p=0.02, respectively).

While both groups saw significant symptom improvement across all IBS-SSS domains, a low-FODMAP diet proved to be significantly better than the OB drug in terms of severity of abdominal distention and the number of days of abdominal pain.

In turn, these symptomatic improvements led to better quality of lives among IBS patients in both groups, with significant difference between diet and OB.

After 16 weeks of follow-up, 99 percent of patients continued keeping their low-FODMAP diets, while only 92 percent remained consistent with OB medication (p=0.001). At 24 weeks, the corresponding rates were still significantly better in the diet arm (98 percent vs 92 percent; p=0.003). Treatment adherence was likewise significantly better in the diet group (94 percent vs 73 percent; p<0.001).

In terms of safety, the researchers reported two serious adverse events but no adverse reactions after randomization to OB. One hospitalization occurred but was unrelated to OB.

“To our knowledge, this is the first large-scale pragmatic trial of a diet application in primary care IBS compared with standard medical therapy,” the researchers said. In the trial, IBS patients allocated to the diet arm were instructed to download a mobile phone app designed to help them make sustainable changes to their dietary behaviours. Two percent of participants did not own a smartphone and were instead given the instructions as a booklet.

Aside from dietary advice, the app also provided participants with a list of food to avoid or cut down on, as well as alternatives and more than 100 recipes.

“In this large primary care IBS cohort, an 8-week usage of a diet application was superior to standard medical therapy. The dietary application was associated to long-lasting significantly higher responder rates and improvement of IBS-SSS,” the researchers added. “Thus, the use of a simple diet application should be considered a first-line approach to manage IBS in primary care.”