Are lower gastrointestinal investigations necessary in patients with coeliac disease?

Colonoscopy may be indicated in patients with coeliac disease who present with iron deficiency anaemia or in coeliac disease patients who have persisting diarrhoea despite being on a gluten-free diet. However, there are limited data to support this approach.

We prospectively recruited patients who were found to have coeliac disease, having been referred with newly diagnosed iron deficiency anaemia. We also recruited a second group of patients with known coeliac disease. These patients had persisting diarrhoea despite being on a gluten-free diet for 6 months. All patients had colonoscopy and were matched with controls (without coeliac disease) who had similar indications for colonoscopy.

Ninety-eight consecutive new patients with coeliac disease and concurrent iron deficiency anaemia had colonoscopy performed. Twelve (12.2%) had pathology, three of which were carcinomas. This diagnostic yield was not significantly different from the findings in the control group 62/362 (17.1%) P=0.24. In coeliac disease patients with persisting diarrhoea (n=37), the diagnostic yield at colonoscopy was 1/37 (2.7%). This was significantly lower than our findings in the control group with chronic diarrhoea 55/390 (14%) P=0.05.

Colonoscopy should be considered in patients with coeliac disease (over the age of 45 years) who present with iron deficiency anaemia. Whilst, for coeliac disease patients with persisting diarrhoea (on a gluten-free diet) in the absence of sinister symptoms, a flexible sigmoidoscopy may be the initial investigation in order to exclude microscopic colitis. However, further larger prospective studies are required to evaluate this approach.