Irritable bowel syndrome is a symptom-based condition defined by the presence of abdominal pain and altered bowel habits – with patients experiencing diarrhea, constipation, or both.
Given the diverse clinical phenotype, it should come as no surprise that the pathogenesis of IBS is also diverse. Studies over the past 60 years have implicated in a wide range of factors in the pathogenesis of IBS including abnormalities in motility, visceral sensation, brain-gut interactions and more recently, genetics, gut dysbiosis including small intestinal bacterial overgrowth, intestinal permeability, and gut immune activation. Environmental factors including food and stress are important, consistently reported triggers for IBS symptoms.
The clinical and pathophysiologic diversity of IBS explains the marginal clinical response to various medical, diet and behavioral treatments. A treatment that targets serotonin receptors, opiate receptors or chloride channels would be expected to benefit only a subset of patients with IBS and in fact, that is exactly what the available randomized controlled trials (RCT) suggest. Most RCTs of IBS treatments report an overall response rate of less than 60% and a therapeutic gain vs. placebo of 10% to 20%. Despite these facts, treatment of IBS in most developed countries has focused on empiric drug therapy.
Intuitive reasoning would suggest that an integrative approach that addresses multiple potential causes and triggers for IBS symptoms might be more successful, particularly for more complex and severely affected patients, than a strategy that relies on medications alone. At present, such a care model is the exception rather than the rule.
The case control study by Bray et al. provides evidence that such an integrative approach offers greater benefits for IBS patients than traditional therapy. This mirrors our own clinical experience at Michigan Medicine. It would be valuable to more formally evaluate the benefits of an integrative care model in a properly designed and powered RCT.
That said, these data lend support to the importance of non-physician providers, such as GI dietitians and behavioral psychologists, as members of the care team for patients with IBS and other functional GI disorders.
Chey WD, et al. JAMA. 2015;313(9);949-958.
Ford AC, et al. Am J Gastroenterol. 2018;113:1-18.
Lenhart A, et al. J Neurogastroenterol Motil. 2018;24:437-451.
Mearin F, et al. Gastroenterol. 2016;150:1393-1407.
William D. Chey, MD
Professor of medicine
Director of the GI Physiology Laboratory
University of Michigan Health System
Disclosures: Chey reports financial ties to Allergan, Conti, IM Health, Ironwood, MyGiHealth, Nestle, QOL Medical, Ritter, Salix, Shire, True Self Foods, Volcant and Zespori.