Patients with established coeliac disease (CD) can present with signs and symptoms requiring small bowel capsule endoscopy (SBCE) to assess for persistent disease beyond the duodenum and to rule out complications. There is paucity of data on extent of disease on SBCE in relation to histology, clinical and serological parameters. The aim of this study was to assess the relationship between symptoms, CD serology and Marsh classification of disease and extent of disease on SBCE in patients with established CD.

Hundred patients with established CD and 200 controls underwent a SBCE. SBCEs were reviewed by expert reviewers. Extent of disease on SBCE, CD findings and small bowel transit were recorded.

Considering duodenal histology (D2; Marsh 3a or above) as the gold standard for diagnosing CD activity, the sensitivity of SBCE to delineate active disease was 87.2%. The specificity was 89.0%. Age at SBCE (P=0.006), albumin (P=0.004) and haemoglobin (P=0.0001), Marsh score of histology from the duodenal bulb (D1) (P=0.0001) and the second part of the duodenum (P=0.0001), refractory CD (P=0.007) on histology correlated with extent of affected small bowel (SB) mucosa on univariate analysis. On multiple regression analysis, albumin (P=0.036) and Marsh score of histology (D1) (P=0.019), vitamin B12 (P=0.001) and folate levels (P=0.008) were statistically significant. Extent of affected SB mucosa (11.0% vs 1.35%) was greater in patients with complications including those with refractory CD (P=0.008).

This is the first study showing correlation between extent of disease and severity of duodenal histology, markers of malabsorption such as folate levels and vitamin B12 and complications of CD.