Screening for autoimmune atrophic gastritis by serum gastrin measurement in subjects with type 1 diabetes

Introduction: Despite associated risk of anemia and gastric cancer, screening for autoimmune atrophic gastritis (AAG) is underperformed in subjects with type 1 diabetes mellitus (T1DM). We measured the predictive value of serum gastrin as a biomarker of gastric atrophy in subjects with T1DM and parietal cell autoantibodies (PCA). Subjects and Methods: PCA measurements were retrospectively retrieved in 1,425 consecutive subjects with T1DM between 2014 and 2018. Screening for AAG was conducted in PCA+ subjects by measuring blood counts, serum ferritin, vitamin B12 and gastrin; and by performing gastroduodenal fibroscopy, with fundic biopsies for histology and Helicobacter pylori. The performance of blood biomarkers of gastric atrophy was analyzed in comparison with the histopathological gold standard. Results: PCA were found in 185/1,425 subjects (13 %). PCA positivity was associated with female sex, older age, longer T1DM duration, and co-occurrence of anti-GAD and anti-thyroperoxydase autoantibodies. Of the 185 PCA+ subjects, 122 (66 %) participated in screening. AAG was found in 69/122 (57 %) subjects and Helicobacter pylori infection in 20/122 (16 %). Compared to PCA+ subjects without gastric atrophy, those with gastric atrophy had more frequently iron deficiency (65 % vs. 18 %, P < 0.0001), and/or vitamin B12 deficiency (57 % vs. 7 %, P < 0.0001); 44/69 (64 %) presented a pre-tumoral lesion and 6 % a tumor. Using a cut-off of 1.2-fold above the upper normal limit, serum gastrin concentration displayed 91 % sensitivity and 82 % specificity at predicting gastric atrophy. Conclusion: In subjects with T1DM and PCA, serum gastrin is a reliable biomarker of gastric atrophy that can be used to select subjects requiring gastroduodenal fibroscopy.