Clinical utility of urinary gluten immunogenic peptides in the follow-up of patients with coeliac disease

Background: Gluten-free diet (GFD) is the only treatment for patients with coeliac disease (CD) and its compliance should be monitored to avoid cumulative damage.

Aims: To analyse gluten exposures of coeliac patients on GFD for at least 24 months using different monitoring tools and its impact on duodenal histology at 12-month follow-up and evaluate the interval of determination of urinary gluten immunogenic peptides (u-GIP) for the monitoring of GFD adherence.

Methods: Ninety-four patients with CD on a GFD for at least 24 months were prospectively included. Symptoms, serology, CDAT questionnaire, and u-GIP (three samples/visit) were analysed at inclusion, 3, 6, and 12 months. Duodenal biopsy was performed at inclusion and 12 months.

Results: At inclusion, 25.8% presented duodenal mucosal damage; at 12 months, this percentage reduced by half. This histological improvement was indicated by a reduction in u-GIP but did not correlate with the remaining tools. The determination of u-GIP detected a higher number of transgressions than serology, regardless of histological evolution type. The presence of >4 u-GIP-positive samples out of 12 collected during 12 months predicted histological lesion with a specificity of 93%. Most patients (94%) with negative u-GIP in ≥2 follow-up visits showed the absence of histological lesions (p < 0.05).

Conclusion: This study suggests that the frequency of recurrent gluten exposures, according to serial determination of u-GIP, could be related to the persistence of villous atrophy and that a more regular follow-up every 6 months, instead of annually, provides more useful data about the adequate adherence to GFD and mucosal healing.