ORIGINAL ARTICLE Is-it possible to distinguish irritable bowel syndrome with constipation from functional constipation? M. Bouchoucha 1,2 • G. Devroede 3 • C. Bon 2 • B. Bejou 2 • F. Mary 2 • R. Benamouzig 2 Received: 31 May 2016 / Accepted: 7 December 2016 Ó Springer International Publishing AG 2017 Abstract Background The Rome III criteria classify patients com- plaining of constipation into two main groups: patients with functional constipation (FC) and patients with con- stipation predominant irritable bowel syndrome (IBS-C). The purpose of this study was to identify differences in the intensity of symptoms and total and segmental colonic transit time in these two types of patients. Methods We performed a prospective evaluation of 337 outpatients consecutively referred for chronic constipation and classified according to the Rome III criteria as FC or IBS-C. They were asked to report symptom intensity, on a 10-point Likert scale, for diarrhea, constipation, bloating and abdominal pain. Stool form was reported using the Bristol scale, and colonic transit time was measured by using multiple-ingestion single-marker single-film tech- nique. Statistical analysis was completed by a discriminant analysis. Results Female gender and obstructed defecation was more frequent in IBS-C patients than in FC patients. IBS-C patients reported greater symptom intensity than FC patients, but stool form, and total and segmental colonic transit time were not different between the two groups. Multivariate logistic regression showed that only two parameters, bloating and abdominal pain, were related to the IBS-C or to the FC phenotype, and discriminant anal- ysis showed that these two parameters were sufficient to give a correct classification of 71% of the patients. Conclusions Our study suggests that self-evaluation of abdominal pain and bloating is more helpful than colonic transit time in classifying patient as IBS-C or FC. Keywords Constipation Á Irritable bowel syndrome Á Abdominal pain Á Bloating Á Functional bowel disorders Introduction The working team of the Rome III criteria for functional gastrointestinal disorders classifies patients complaining of constipation into two main groups: patients with functional constipation (FC) and patients with constipation predomi- nant irritable bowel syndrome (IBS-C) [1]. This classifi- cation into distinct disorders suggests that they have different pathophysiological mechanisms and therefore could require different treatment approaches. The Rome III criteria define irritable bowel syndrome (IBS) as ‘‘a functional bowel disorder in which abdominal pain or discomfort is associated with defecation or a change in bowel habit, and with features of disordered defecation’’ [1] and defines FC as ‘‘a functional bowel disorder that presents as persistently difficult, infrequent, or seemingly incomplete defecation, which do not meet IBS criteria’’ [1]. Moreover, an overlap between FC and IBS-C, and switches between these diagnoses over time was shown [2] leading the authors to consider FC and IBS-C as defined by the Rome III criteria, as not being distinct entities. Nevertheless, the authors underlined that the limits of their study was the absence of the measurement of relevant physiological parameters such as whole gut transit time, & M. Bouchoucha michel.bouchoucha@avc.aphp.fr 1 Department of Physiology, Paris Descartes University, Paris, France 2 Gastroenterology Department, Avicenne Hospital Bobigny, 93009 Bobigny Cedex, France 3 Department of Surgery, Sherbrooke University Medical School, Sherbrooke, Canada 123 Tech Coloproctol DOI 10.1007/s10151-016-1580-x