Spotlight on functional GI disorders

Research in the past month focused on irritable bowel syndrome (IBS) and functional dyspepsia, finding a worse disease prognosis among patients with both conditions versus IBS alone, as well as sex-based differences and an inverse association between fruit intake and functional dyspepsia symptoms.


Recent studies looked at the two most common functional GI disorders, irritable bowel syndrome (IBS) and functional dyspepsia.

The first study found that patients with IBS with overlapping functional dyspepsia are more likely to seek health care and have a worse disease prognosis than those with IBS alone. Researchers conducted a longitudinal follow-up study in a cohort of 1,374 adults in the U.K. who self-identified as having IBS and used an online questionnaire to report demographic, symptom, mood, and psychological health data. They applied Rome IV criteria to determine what proportion met criteria for IBS and functional dyspepsia, as well as the degree of overlap between the two conditions. At 12 months, a questionnaire collected data regarding IBS symptom severity and impact, consultation behavior, treatments, and psychological health according to the degree of overlap between IBS and functional dyspepsia. Results were published online on April 8 by Clinical Gastroenterology and Hepatology.

Overall, 811 (59.0%) participants met Rome IV criteria for IBS at baseline, of which 807 (99.5%) provided complete data for the analyses. Of these, 361 (44.7%) participants were classified as having IBS alone, 208 (25.8%) as having IBS and postprandial distress syndrome, 60 (7.4%) as having IBS and epigastric pain syndrome, and 178 (22.1%) as having IBS with overlapping postprandial distress syndrome and epigastric pain syndrome. At 12 months, 451 (55.9%) of 807 participants completed follow-up, and IBS subtype remained relatively stable from baseline in the four groups. During the 12-month follow-up, the proportion who consulted their primary care physician (36.4% of those with IBS alone vs. 59.6% of those with IBS with overlapping postprandial distress syndrome and epigastric pain syndrome; P=0.001) or a gastroenterologist (16.8% of those with IBS alone vs. 44.4% with IBS with overlapping postprandial distress syndrome and epigastric pain syndrome; P<0.001) for their IBS increased with the degree of overlap between IBS and functional dyspepsia. The number of new treatments started for IBS was higher in patients with IBS with overlapping postprandial distress syndrome and epigastric pain syndrome (P=0.007 for trend). In addition, those with IBS and functional dyspepsia overlap reported more symptoms, which had a significantly greater impact on activities of daily living, and were more likely to report continuous abdominal pain and impaired psychological health. Among other limitations, the researchers noted that they did not check medical records to rule out GI conditions that may masquerade as IBS (e.g., celiac disease and inflammatory bowel disease).

The second analysis, a thematic review on women's health for practitioners, found that there are sex- and gender-based differences in the prevalence and clinical characteristics of IBS and functional dyspepsia. Similar to other disorders accompanied by chronic pain (e.g., fibromyalgia, migraine, and rheumatoid arthritis), both IBS and functional dyspepsia are more common in women than men, according to the review, which was published in the April Mayo Clinic Proceedings.

Among patients with IBS, women are more likely to have severe symptoms and coexisting anxiety or depression, and severity of anxiety correlates with some IBS symptoms in women but not in men. Constipation or bloating is more common in women with IBS, whereas diarrhea is more common in men with IBS, “perhaps partly because defecatory disorders, which cause constipation, are more common in women,” the review said. In addition, women with IBS are more likely than men to seek health care. In functional dyspepsia, the male-to-female ratio is comparable in patients with epigastric pain syndrome and/or postprandial distress syndrome. In addition, female sex is an independent risk factor for delayed gastric emptying for patients with functional dyspepsia. Regarding clinical management, “Whether sex or gender affects response to medications or behavioral therapy in [functional dyspepsia] or IBS is unclear because most patients in these studies are women,” the review authors wrote.

The final study found an inverse association between fruit intake and functional dyspepsia symptoms. Researchers conducted the cross-sectional study in 3,362 middle-age participants in Iran. They assessed usual dietary intakes, including fruit and vegetable intake, during the last year using a validated 106-item food frequency questionnaire and used a modified Persian version of the Rome III questionnaire to assess the presence of functional dyspepsia. Results were published online on April 2 by Neurogastroenterology & Motility.

The overall prevalence of functional dyspepsia was 14.5%. After adjustment for confounders, the highest energy-adjusted tertile of fruit consumption was associated with a 32% lower risk of functional dyspepsia compared to the lowest intake (odds ratio [OR], 0.68; 95% CI, 0.51 to 0.90). Fruit consumption was also significantly related to lower risk of early satiation (OR, 0.67; 95% CI, 0.54 to 0.85) and postprandial fullness (OR, 0.75; 95% CI, 0.61 to 0.92). In contrast, vegetable consumption was not related to the risk of functional dyspepsia in all models. Men who were in the third tertile of fruit and vegetable consumption had lower risk of functional dyspepsia compared to the first tertile, but in women, only fruit consumption was related to the reduced risk of functional dyspepsia, after adjustment for all confounders. The study was limited by its lack of randomization and the fact that the questionnaires were self-administered, the authors noted.