Disorders of the gut-brain interaction, including irritable bowel syndrome (IBS) and functional dyspepsia (FD), often overlap. However, the effect of this overlap is not clearly understood on the natural history.

Therefore, Barberio and colleagues conducted a longitudinal follow-up study in a large cohort of individuals to determine this impact.

Demographic, symptom, mood, and psychological health data were obtained from 1374 adults self-reporting as having IBS. The Rome IV criteria was used to ascertain the proportion that fulfilled the criteria for IBS and FD, and the degree of overlap between them. At 12 months, data were collected on IBS symptom severity and impact, consultation behavior, treatment initiated, and psychological health based on degree of overlap between IBS and FD.

A total of 807 individuals met the Rome IV criteria for IBS at baseline and provided complete data.

• At study initiation, overlap of FD was noted in 446 (55.3%) individuals who met Rome IV criteria for IBS.
• At 12 months, 451 (55.9%) individuals were followed-up.
• The proportion of people consulting a primary care physician (P = 0.001) or a gastroenterologist (P < 0.001) for IBS was significantly higher in those having an overlap of IBS and FD. The number of new IBS treatments started was also significantly higher (P = 0.007).
• People with overlap of IBS and FD had significantly more severe IBS symptoms (P < 0.001), continuous abdominal pain. Their IBS symptoms also restricted normal daily activities ≥50% of the time.
• People with overlap of IBS and FD had higher odds of reporting abnormal anxiety and depression scores at 12 months in comparison with people having only IBS. They were also more likely to have higher levels of somatization (P < 0.001 for all analyses).

The natural history of individuals with IBS with overlap FD as per the Rome IV criteria is more severe compared to those with IBS only.

Source: Barberio B, Yiannakou Y, Houghton LA, et al. Overlap of Rome IV Irritable Bowel Syndrome and Functional Dyspepsia and Effect on Natural History: A Longitudinal Follow-Up Study. Clin Gastroenterol Hepatol. 2022 Feb;20(2):e89-e101.