Overlap of Irritable Bowel Syndrome and Functional Dyspepsia in the Clinical Setting: Prevalence and Risk Factors
According to Rome IV criteria, functional dyspepsia (FD) and irritable bowel syndrome (IBS) are distinct functional gastrointestinal disorders (FGID); however, overlap of these conditions is common in population-based studies, but clinical data are lacking.
To determine the overlap of FD and IBS in the clinical setting and define risk factors for the overlap of FD/IBS.
A total of 1127 consecutive gastroenterology outpatients of a tertiary center were recruited and symptoms assessed with a standardized validated questionnaire. Patients without evidence for structural or biochemical abnormalities as a cause of symptoms were then categorized based upon the symptom pattern as having FD, IBS or FD/IBS overlap. Additionally, this categorization was compared with the clinical diagnosis documented in the integrated electronic medical records system.
A total of 120 patients had a clinical diagnosis of a FGID. Based upon standardized assessment with a questionnaire, 64% of patients had FD/IBS overlap as compared to 23% based upon the routine clinical documentation. In patients with severe IBS or FD symptoms (defined as symptoms affecting quality of life), the likelihood of FD/IBS overlap was substantially increased (OR = 3.1; 95%CI 1.9–5.0) and (OR = 9.0; 95%CI 3.5–22.7), respectively. Thus, symptom severity for IBS- or FD symptoms were significantly higher for patients with FD/IBS overlap as compared to patients with FD or IBS alone (p all < 0.01). Age, gender and IBS-subtype were not associated with overlap.
In the clinical setting, overlap of FD and IBS is the norm rather than the exception. FD/IBS overlap is associated with a more severe manifestation of a FGID.
KeywordsFunctional gastrointestinal disorders Functional dyspepsia Irritable bowel syndrome Symptom severity
The authors would like to thank all consultants, fellows, nurses and administrative staff of the Department of Gastroenterology and Hepatology of the Princess Alexandra Hospital for their contributions to the clinical assessment and treatment of the patients. Special thanks to Jenny Scott and Elizabeth Debowski for their administrative support.
MvW and GH were involved in planning and conducting the study, data collection, analyzing and interpretation of data, drafting of manuscript, and final review of manuscript. JH contributed to the concept and design, data collection, important intellectual input, and critical review of manuscript. MJ was involved in data analysis and critical review of the manuscript. JM, GR, AS, NK, BK and NT contributed to important intellectual input, important contribution to study planning, and critical review of manuscript.
This work was supported by an unrestricted Grant from Diamantina Health Partners in Brisbane, Australia, funding from the PAH Foundation and the National Health and Medical Research Council (NHMRC).
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Conflict of interest
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