Long-term natural history of autoimmune gastritis: results from a prospective, monocentric series

Abstract

Objectives: The natural history of autoimmune gastritis (AIG) has been poorly described. We herein report the long-term natural history and clinical clustering of the full spectrum of AIG, from the potential to the complicated stage. Methods: Prospective, single-center study conducted in a tertiary referral center. AIG patients at any stage (0=potential; 1=early; 2=florid; 3=severe; 4=complicated) were enrolled (January 2000-December 2022). The histopathological evolution, the clinical presentation, and the correlates of evolution of potential AIG were assessed. Results: 498 AIG patients (mean age 56.7±15.2, F:M ratio 2.5:1) were included, of whom 93 with potential AIG. The maximum disease duration was 27 years (median 18, IQR 14-23), while the overall median follow-up was 52 months (IQR 12-95). Age was significantly lower in stage 0 compared to the other stages. Accidental histologic evidence and hematologic findings were the most common clusters of diagnosis. The overall median rate of progression was 7.29 per 100 person/year (95% CI 6.19-8.59), while the stage-specific rates of progression were 10.85 (stage 0; 95% CI 7.75-15.18), 14.83 (stages 1-2; 95% CI 11.89-18.49), and 2.68 (stage 3; 95% CI 1.88-3.84). Newly onset neoplastic complications at follow-up occurred in 41/483 patients (8.5%; 23 neuroendocrine tumors, 18 epithelial dysplasia). No cases of adenocarcinoma were noticed. Male sex was associated with a greater likelihood of evolving from potential AIG to overt AIG. Conclusions: AIG is a progressive disorder, with a virtually absent risk of gastric adenocarcinoma. Potential AIG patients should be monitored as they carry a high risk of evolving into overt AIG.