Description:
<jats:sec><jats:title>Background</jats:title><jats:p>The classical definition of chronic diarrhoea is ≥3 defecations/day, with a stool weight of more than 200 g and duration of ≥4 weeks. However, with this definition many patients with substantial symptoms and pathology will be excluded from further investigations. As a consequence other definitions have been proposed, mainly based on evaluation of the stool form.</jats:p></jats:sec><jats:sec><jats:title>Objective</jats:title><jats:p>To evaluate the accuracy of the classic criteria for diarrhoea in comparison with a definition based on stool consistency, using the Bristol Stool Form Scale.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>All patients were investigated with laboratory tests, upper and lower gastrointestinal endoscopy with biopsies, and SeHCAT test. They were asked to complete a diary recording stool frequency and consistency during a week, as well as other gastrointestinal symptoms (pain, bloating and gas).</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>One hundred and thirty‐nine subjects were eligible for analysis. Ninety‐one had an organic cause of diarrhoea. Fifty‐three patients had ≥3 loose stools/day, whereas 86 reported <3 stools/day. Ninety had a median stool consistency that was mushy or loose and 49 had harder stools. A higher proportion of subjects with an organic cause of their diarrhoea compared with subjects with a functional bowel disorder had ≥3 loose stools/day, 43/91 (47%) <jats:italic>vs</jats:italic>. 10/48 (21%) (<jats:italic>p</jats:italic> < 0.01). Similarly, more subjects with an organic cause of their diarrhoea versus patients with a functional bowel disorder had a median stool consistency that was mushy or watery, 73/91 (80%) <jats:italic>vs</jats:italic>. 17/48 (35%), <jats:italic>p</jats:italic> < 0.0001. When diarrhoea was defined according to stool form, more patients were classified correctly as having a functional disorder or organic disorder, compared with the classical definition (<jats:italic>p</jats:italic> < 0.05).</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>Loose stools defined according to the Bristol Stool Form scale seem to be the best predictor of having an organic cause of the diarrhoea.</jats:p></jats:sec>