[Preliminary study on the value of serum pepsinogen in differentiating autoimmune gastritis].

Objective: This study identifies independent predictive indicators to distinguish autoimmune gastritis from Helicobacter pylori (H. pylori)-induced atrophic gastritis and validates their diagnostic performance to compare laboratory indicators of autoimmune gastritis and H. pylori-induced atrophic gastritis. Methods: A retrospective comparison of laboratory examination indicators was conducted for chronic atrophic gastritis patients with involvement of the gastric fundus and corpus, who were followed up at the Department of Gastroenterology, Xijing Hospital, from January 2014 to September 2024. Receiver operating characteristic (ROC) curves were utilized to determine the optimal cutoff points and corresponding diagnostic thresholds. In addition, multivariate logistic regression analysis was conducted to identify independent predictive indicators for autoimmune gastritis, with further assessment in a validation cohort. Results: A total of 139 patients with autoimmune gastritis and 209 patients with H. pylori-induced atrophic gastritis were included. Pepsinogen (PG) Ⅰ levels and the PG Ⅰ/PG Ⅱ ratio in patients with autoimmune gastritis were significantly lower than in those with H. pylori-induced atrophic gastritis [11.0 (4.8, 22.5) vs. 41.8 (32.2, 59.9) μg/L, U=722.00, P<0.001; 1.24 (0.75, 3.54) vs. 5.76 (4.31, 7.12), U=817.00, P<0.001], while gastrin levels were significantly higher [375 (84, 738) vs. 49 (35, 81) ng/L, U=378.00, P<0.001]. PG Ⅰ was identified as an independent predictive variable, with an area under the ROC curve of 0.847 (95%CI 0.791-0.904), sensitivity of 77.6%, specificity of 91.8%, positive predictive value of 80.5%, and negative predictive value of 90.5%. Conclusions: Significant differences in laboratory indicators were observed between autoimmune gastritis and H. pylori-induced atrophic gastritis in chronic atrophic gastritis involving gastric fundus and corpus. Besides, PG Ⅰ demonstrated good diagnostic performance in identifying autoimmune gastritis and can effectively differentiate between different types of atrophic gastritis.