Role of HLA‐DQ typing and anti‐tissue transglutaminase antibody titers in diagnosing celiac disease without duodenal biopsy in type 1 diabetes: A study of the population‐based pediatric type 1 diabetes cohort of Western Australia.

Aim: The primary aim of the present study was to determine if it is cost effective to use human leukocyte antigen (HLA) typing as a first‐line screening test for celiac disease (CD) in children with type 1 diabetes (T1D), as recommended by the European Society of Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN). The second aim was to investigate whether anti‐tissue transglutaminase IgA (anti‐tTGA) antibodies can be used to diagnose CD without the need for a confirmatory duodenal biopsy in T1D. Methods: Data for all T1D patients aged <18 years, who attended the diabetes clinics in Western Australia up to June 2017, were extracted from the Western Australian Children's Diabetes Database (WACDD) and analyzed for their demographic data and CD permissive HLA alleles (DQ2, DQ8, and DQ7). For T1D patients already diagnosed with CD, the mode of diagnosis of CD, anti‐tTGA titers, and CD permissive HLA alleles were analyzed. Results: Of the 936 eligible T1D patients identified, HLA‐DQ typing was available for 551 (59%). Of these 551 patients, 504 (91.2%) were positive for celiac permissive HLA alleles. Eight percent (n = 75) of the T1D patients had a co‐diagnosis of CD. High anti‐tTGA titers were observed in those who were diagnosed with a positive duodenal biopsy. Conclusion: HLA‐DQ typing is not cost effective as a first‐line screening test for CD in T1D patients because of over‐representation of CD permissive HLA alleles in this group. Anti‐tTGA titers may be useful in diagnosing CD in T1D without duodenal biopsy, as high levels were found to be strongly predictive of CD. [ABSTRACT FROM AUTHOR]