Meta‐analysis: factors affecting placebo response rate in the irritable bowel syndrome

Abstract

SUMMARY BackgroundIrritable bowel syndrome (IBS) is a functional disorder of the gastrointestinal tract with a significant placebo response.

Utility of Food Patch Testing in the Evaluation and Management of Irritable Bowel Syndrome

“…Additionally, placebo effect is most prevalent for conditions such as IBS where primarily subjective outcome measures are available 20 , with a prevalence of up to 40% in IBS 21 . In a 1999 report 22 , Spiller analyzed 25 randomized, placebocontrolled IBS clinical trials, observing that placebo effect begins to diminish after about 12 weeks.…”

Comment on “A randomized clinical trial of Saccharomyces cerevisiae versus placebo in the irritable bowel syndrome” by Guillaume Pineton de Chambrun et al. [Digestive and Liver Disease 2015;47:119–24]

“…While these data are encouraging, changes in individual symptom scores from baseline were similar in the placebo arm, reflecting the high placebo response rate in IBS, 5 and highlighting the fact that, despite the authors conclusions that SC reduces abdominal pain and discomfort scores, it performed similarly to placebo in this RCT.…”

Fecal excretion of Bifidobacterium infantis 35624 and changes in fecal microbiota after eight weeks of oral supplementation with encapsulated probiotic

“…It is widely recognized that placebo response rates across randomized controlled trials of therapies in IBS are high. 36 In summary, our investigation demonstrated that during 8 weeks of daily supplementation with 10 9 cfu of the encapsulated B. infantis 35624, fecal excretion of this microbe rose to comparable levels both in healthy subjects and subjects with IBS, whereas excretion remained relatively unchanged in subjects with IBS that received placebo. This suggests that the probiotic is able to survive transit through the GI tract, although strain selective culture techniques were not performed to confirm viability of B. infantis 35624 in the feces.…”