What is the Role of Measuring Urinary Gluten Immunogenic Peptides in Clinical Practice in Patients with Coeliac Disease?

Background & Aims: In coeliac disease, the clinical role of the urinary gluten immunogenic peptide is unclear. It has been suggested it can be a non-invasive marker of villous atrophy. Therefore, we present the largest cross-sectional clinical data in patients with coeliac disease to establish the diagnostic accuracy of the urinary gluten immunogenic peptide in identifying villous atrophy. Methods: Patients providing urinary gluten immunogenic peptide were identified between September 2018 and August 2023 at the National Health Service (NHS) England National Centre for Non-Responsive and Refractory CD. In our retrospective study, the results of the urinary gluten immunogenic peptide test collected within 7 days, self-reported adherence to a gluten free diet reported within 3 months, serology collected within 7 days (immunoglobulin A - tissue transglutaminase and endomysial antibody) and histology at the time of endoscopy were compared in individuals with coeliac disease who were either asymptomatic and undergoing remission biopsies (group 1), non-responsive coeliac disease (group 2) and refractory coeliac disease on immunosuppressive therapy (group 3). Associations between dichotomous variables were calculated using chi-squared test. Results: In group 1 the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for detecting villous atrophy were 42.9%, 83.3.%, 64.3% and 67.6% respectively. In group 2 the sensitivity, specificity, PPV and NPV for detecting villous atrophy were 36.2%, 79.0%, 39.5% and 76.6% respectively. In group 3 the sensitivity, specificity, PPV and NPV for detecting villous atrophy were 56.3%, 70.6%, 73.0% and 53.3%. More patients on immunosuppression had a positive urinary gluten immunogenic peptide than those not on immunosuppression (43.3% vs 24.1%, p<0.001). Conclusions: The urinary gluten immunogenic peptide does not have a role in identifying villous atrophy. Therefore, to assess for villous atrophy an upper gastrointestinal endoscopy is still required. [ABSTRACT FROM AUTHOR]