Risk of Gastric Neoplasms in Patients with Autoimmune Gastritis: A Systematic Review and Meta-Analysis

Background/Aims: Autoimmune gastritis (AIG) underlies type 1 gastric neuroendocrine tumors (NETs) and pernicious anemia (PA), a late-stage manifestation of AIG.Although PA is a risk factor for gastric cancer (GC), the independent neoplastic risk of AIG and the modifying role of Helicobacter pylori infection remain uncertain.We evaluated the risk of gastric neoplasms in patients with AIG and assessed associations with PA and H. pylori exposure.Methods: A PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses)guided systematic review and meta-analysis were performed.PubMed, EMBASE, and the Cochrane Library were searched for studies of gastric neoplasms in adults with AIG or PA.Pooled incidence rates and risk estimates were calculated.Between-study heterogeneity was explored by using meta-regression.Publication bias, sensitivity, and H. pylori-stratified subgroup analyses were performed.Results: In patients with AIG, pooled incidence rates (per 1,000 person-years) were 2.08 for GC, 5.35 for dysplasia, and 14.56 for NETs.The GC incidence was not statistically significant overall but became significant in sensitivity analyses when the Rugge et al. cohort was excluded.The dysplasia and NET incidence rates were significantly elevated.In patients with PA, GC risk was consistently elevated (relative risk, 2.78; standardized incidence ratio, 2.69).Meta-regression analysis identified age and diagnostic criteria as contributors to GC heterogeneity.Patients with H. pylori-positive AIG showed a trend toward reduced GC and NET risks.Conclusions: AIG was associated with increased risks of dysplasia and NETs, and GC risk might be underestimated in the presence of substantial heterogeneity.PA was associated with a higher risk of GC.Endoscopic surveillance may be considered in patients with AIG, particularly for dysplasia, NET, and GC risks in those with concomitant PA. (Gut Liver, Published online M ay 6, 2026)