Overlapping upper and lower gastrointestinal symptoms in irritable bowel syndrome patients with constipation or diarrhea.

Objectives: Distinguishing between irritable bowel syndrome (IBS) and functional dyspepsia can be challenging because of the variations in symptom patterns, which commonly overlap. However, the overlap is poorly quantified, and it is equally uncertain whether symptom patterns differ in subgroups of IBS arbitrarily defined by primary bowel patterns of constipation (IBS-C) and diarrhea (IBS-D). We aimed to determine and to compare the distribution of GI symptoms, both, upper and lower, among IBS-C and IBS-D patients.