First IBS Guideline Based on GRADE Methodology Published

The first-ever clinical guideline using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology for the diagnosis and management of irritable bowel syndrome (IBS) has been published by the American College of Gastroenterology.

This guideline offers recommendations on 25 clinically important points concerning IBS. Trained GRADE methodologists reviewed relevant medical literature to assess the quality of evidence available on each point and to arrive at the strength of each recommendation.

The authors strongly recommended:

  • Applying a positive diagnostic strategy rather than a strategy of exclusion, to prevent delays in initiating appropriate therapy and to improve cost-effectiveness.
  • Performing serologic testing to rule out celiac disease among patients with IBS and diarrhea symptoms.
  • Checking fecal calprotectin and C-reactive protein among patients with diarrhea symptoms to rule out inflammatory bowel disease.
  • Prescribing tricyclic antidepressants to treat global symptoms of IBS.
  • Using chloride channel activators and guanylate cyclase activators to treat global IBS with constipation symptoms.
  • Using rifaximin to treat global IBS with diarrhea symptoms.
  • Applying gut-directed psychotherapy to treat global IBS symptoms.
  • Using soluble, but not insoluble, fiber to treat global IBS symptoms.

In a consensus recommendation that could not be assessed using GRADE methodology, the authors further suggested that categorizing patients with IBS based on an accurate subtype can improve patient therapy. Among the conditional recommendations is a limited trial of a low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols diet.

The authors acknowledged that “as this extensive project evolved, we recognized that there are still significant gaps in our knowledge. Future research is needed to better understand the role of the gut microbiome in patients with IBS and to understand the genesis of visceral pain.” They also called for the identification of biomarkers to predict treatment response and head-to-head trials to test therapies, both of which will enable clinicians to provide individualized care.


—Rebecca Mashaw



Lacy BE, Pimentel M, Brenner DM, et al. ACG clinical guideline: management of irritable bowel syndrome. Am J Gastroenterol 2020;00:1–28. Published online December 14, 2020.