Influence of the requirement for abdominal pain in the diagnosis of irritable bowel syndrome with constipation (IBS-C) under the Rome IV criteria using data from a large Japanese population-based internet survey

BACKGROUND: Rome III was revised to Rome IV in May 2016. One important change in the Rome IV criteria is that abdominal pain must be present for a diagnosis of irritable bowel syndrome (IBS). Under Rome III, in contrast, patients with abdominal discomfort only could be diagnosed with IBS, but these cases under Rome IV are now classified as unspecified functional bowel disorder (FBD). In a simple comparison of Rome III and Rome IV, it is unclear whether this difference reflects the influence of symptomatic frequency or the presence of abdominal pain. In particular, the influence of abdominal pain restriction on the diagnosis of IBS with predominant constipation (IBS-C) in the Rome IV criteria is largely unknown. METHODS: We reclassified subjects from a Japanese internet survey experiencing abdominal pain or discomfort at least one day each week as surrogate Rome III IBS-C subjects. Among them, we then reclassified subjects experiencing abdominal pain as surrogate Rome IV IBS-C subjects and subjects not experiencing abdominal pain as surrogate Rome IV FBD subjects. Symptoms were quantified and compared between the two groups. RESULTS: The surrogate Rome IV IBS-C subjects felt a significantly higher degree of anxiety in their daily lives (p < 0.001) compared with the surrogate Rome IV FBD subjects. The combined female and 20–49 years surrogate Rome IV IBS-C subjects felt a higher degree of anxiety in their daily lives (p < 0.05) than the respective Rome IV FBD subjects. CONCLUSIONS: These results suggest that female IBS-C patients aged 20–49 years with abdominal pain in Rome IV have more anxiety than those without abdominal pain in Rome III. Changes in the diagnostic criteria from Rome III to Rome IV will better identify candidates for the biopsychosocial approach. TRIAL REGISTRATION: Although this survey was an anonymous internet survey, we obtained informed consent for the study as an online response. The disclosure of this study was approved by the Ethics Committee of Tohoku University Graduate School of Medicine (approval number: 2015–1-405).