Are the definitions for chronic diarrhoea adequate? Evaluation of two different definitions in patients with chronic diarrhoea.
BACKGROUND
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.


OBJECTIVE
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.


METHODS
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).


RESULTS
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%) vs. 10/48 (21%) (p < 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%) vs. 17/48 (35%), p < 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 (p < 0.05).


CONCLUSIONS
Loose stools defined according to the Bristol Stool Form scale seem to be the best predictor of having an organic cause of the diarrhoea.
Department of Internal Medicine, Sahlgrenska University Hospital, Göteborg, Sweden.
Per-Ove
PO
Stotzer
Department of Internal Medicine, Sahlgrenska University Hospital, Göteborg, Sweden.
Hasse
H
Abrahamsson
Department of Internal Medicine, Sahlgrenska University Hospital, Göteborg, Sweden.
Antal
A
Bajor
Department of Internal Medicine, Sahlgrenska University Hospital, Göteborg, Sweden.
Anders
A
Kilander
Department of Internal Medicine, Sahlgrenska University Hospital, Göteborg, Sweden.
Riadh
R
Sadik
Department of Internal Medicine, Sahlgrenska University Hospital, Göteborg, Sweden.
Henrik
H
Sjövall
Department of Internal Medicine, Sahlgrenska University Hospital, Göteborg, Sweden.
Magnus
M
Simrén
Diarrhoea; bile acid diarrhoe; definition of diarrhoea; investigation of diarrhoea; microscopic colitis