Diagnostic outcomes after gluten challenge in adult patients with unconfirmed coeliac disease already on a gluten‐free diet: A 20‐year retrospective cohort study

Background

In uncertain cases of coeliac disease (CD), gluten challenge (GC) may be necessary to confirm or exclude the diagnosis. However, data on diagnostic outcomes after GC are limited.

Aims

We aimed to evaluate outcomes after GC in patients with unconfirmed CD who had already started a gluten-free diet (GFD), and identify predictors of a confirmed diagnosis.

Methods

Patients with unconfirmed CD already on a GFD, who underwent GC and subsequent testing with endomysial antibodies (EmA) and duodenal biopsy between 06/2000–06/2021 were included. Clinical data, prior test results, and final diagnoses were retrospectively collected and analysed.

Results

158 patients underwent GC (median duration 3 months, IQR 3–6) and CD was confirmed in 47/158 (29.7 %) (41 conventional CD, 1 CD + IgAdeficiency, 5 potential CD), non-coeliac enteropathies (NCEs) were diagnosed in 3 patients, and enteropathy was ruled out in 108. Prior positive serology strongly predicted CD diagnosis after GC (OR 36.8, 95 %CI 13.8–100.0, p < 0.001), whereas prior reported villous atrophy did not (p = 0.83), as this was frequently (35 %) due to incorrect sampling/interpretation of poorly oriented specimens. Duration of GC was also not associated with diagnostic outcomes (p = 0.37).

Conclusion

Prior positive serology strongly predicted CD diagnosis after GC, while histological results without positive serology should be interpreted cautiously. Clinicians should consider NCEs in older patients with severe symptoms.