Background and aims: Methods of assessing gluten-free diet (GFD) adherence in adults with coeliac disease (CD) include serological testing, dietitian evaluation, questionnaires and repeat duodenal biopsies. Persisting villous atrophy (VA) is associated with CD complications, however gastroscopy with biopsies is expensive and invasive. This study aimed to assess the abilities of a duodenal bulb (D1) biopsy and the Celiac Dietary Adherence Test (CDAT) to detect persisting VA in adults with CD.
Methods: A prospective observational study of adult CD patients referred for follow-up duodenal biopsies was performed. Quadrantic biopsies were taken from the second part of the duodenum (D2), in addition to a D1 biopsy. Patients underwent follow-up serological testing, and completed the CDAT and Biagi Score. These non-invasive adherence markers were compared against duodenal histology.
Results: 368 patients (mean age 51.0 years, 70.1% female) had D1 and D2 biopsies taken at follow-up gastroscopy. Compared to D2 biopsies alone, additional D1 biopsies increased detection of VA by 10.4% (p<0.0001). 201 patients (mean age 50.3 years, 67.7% female) completed adherence questionnaires and serology. When detecting VA, sensitivities and specificities of these markers were 39.7% and 94.2% for IgA- tTG, 38.1% and 96.4% for IgA-EMA, 55.6% and 52.2% for CDAT and 20.6% and 96.4% for the Biagi score.
Conclusions: Bulbar biopsies increase detection of persisting VA by 10.4%. Serology, CDAT and Biagi performed poorly when predicting VA. The gold standard for predicting persisting VA remains repeat biopsy.