P0928 - Diagnosing Celiac Disease in Adults Without the Need for Biopsy, Is It Possible? A Retrospective Study on Anti-Tissue Transglutaminase Antibody Titers and Duodenal Biopsy Results

Award: Outstanding Research Award in the Small Intestine Category (Trainee)
Award: Presidential Poster Award

Award: Outstanding Research Award in the Small Intestine Category (Trainee)

Award: Presidential Poster Award

Kenza Achtoutal, MD, Marie-Pier Bachand, MD
Université de Sherbrooke, Sherbrooke, PQ, Canada

Introduction: Current guidelines from the American College of Gastroenterology recommend confirming diagnosis of celiac disease (CD) with duodenal biopsies. However, the latest guidelines on CD from the European Society of Paediatric Gastroenterology Hepatology and Nutrition provide new criteria to diagnose CD in children without the need for biopsy. Given the current COVID-19 pandemic, access to upper endoscopy in a timely manner is becoming increasingly difficult. The question of confidently diagnosing CD without biopsies in adult patients is clinically relevant. The primary objective of this study is to define a level of anti-tissue transglutaminase antibody (aTTG) for which histology results are consistently positive.

Methods: We performed a retrospective study of 732 adult patients with positive aTTG titers from 2010 to 2019 at the CIUSSS de l’Estrie CHUS.




Patients who did not undergo gastroscopy or already had a confirmed diagnosis at the time of the study were excluded. We calculated the sensitivity and specificity for aTTG serology. Using ROC curve and Youden index we determined the optimal cut-off for aTTG titers as well as the antibody level at which positive predictive value (PPV) was 100%. We also collected data on demographics, personal and familial medical history and symptoms on presentation.

Results:
Our final database included 440 patients from which 364 had a diagnosis of CD.
66.8% of the patients were female with a mean age of 50.3 years. 15.4% of patients had a family history of CD and 9% had a positive past medical history for autoimmune diseases. 93.1% of patients were symptomatic at the time of the study with diarrhea being the most frequent form of presentation (40.1%). The ROC curve had an area under the curve of 89.3% [86.1;92.4]. Using the Youden Index, the optimal cut-off for IgA-TTG titers was 2.8 times the upper limit of normal (ULN) with a sensitivity of 81.04% and specificity of 88.16%. To achieve a PPV of 100%, the cut-off for aTTG titers was 8.76 ULN with a sensitivity of 50% and a specificity of 100%. In other words, every patient with an aTTG titer above 8.76 ULN had a confirmed diagnosis of CD. Of note, none of the patients with a potential CD (positive serology, unremarkable histopathology) developed complications during a 2-year period after initial biopsy.







Discussion: In this study, every adult patient with an aTTG titer > 8.76 ULN had a confirmed diagnosis of CD which means that CD diagnosis could be made without the need for duodenal biopsy.


Disclosures:
Kenza Achtoutal indicated no relevant financial relationships.
Marie-Pier Bachand indicated no relevant financial relationships.


Kenza Achtoutal, MD, Marie-Pier Bachand, MD. P0928 - Diagnosing Celiac Disease in Adults Without the Need for Biopsy, Is It Possible? A Retrospective Study on Anti-Tissue Transglutaminase Antibody Titers and Duodenal Biopsy Results, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.