Overlap of gastrointestional symptom complexes in a US community

Background: Although the Rome criteria define a number of individual functional gastrointestinal disorders, people may have symptoms of multiple disorders at the same time. In addition, therapies may be effective in subsets of people with specific disorders, yet at the same time help people with multiple disorders. Aim: To estimate the prevalence of combinations of gastrointestional (GI) symptom complexes. Methods: A valid self report questionnaire which records GI symptoms was mailed to an age- and gender-stratified random sample of Olmsted County, MN residents aged 30-64 years. Standard definitions were used to identify people with gastro-oesophageal reflux, dyspepsia, irritable bowel syndrome (IBS), constipation and diarrhoea. The prevalence of people meeting multiple symptom complexes was estimated. Specifically, combinations of dyspepsia, IBS and constipation were compared to dyspepsia, IBS and diarrhoea. Results: A total of 657 (69%) of 943 eligible subjects responded; 643 provided data for each of the necessary symptom questions. Each two-way combination of symptom group was present in between 4 and 9% of the population; each three-way combination was present in 1-4% of the population. The overlap between dyspepsia, IBS and constipation was similar to dyspepsia, IBS and diarrhoea, except body mass index was higher in the diarrhoea overlap group (P = 0.03). Conclusion: Symptom complex overlap is common in the community; for each condition, the majority of sufferers reported an additional symptom complex. This overlap of symptoms challenges the current paradigm that functional GI disorders represent multiple discreet entities.