Autoimmune Gastritis and Gastric Cancer Risk: Endoscopic and Histopathological Outcomes

Background and Aims: Autoimmune gastritis (AIG) is a chronic immune-mediated condition characterized by corpus-predominant atrophy, which can lead to vitamin B12 deficiency, achlorhydria, and an increased risk of gastric adenocarcinoma (GC) and neuroendocrine tumours. Diagnosis is often challenging due to a long asymptomatic phase and variable clinical presentation. This study aimed to assess the prevalence of gastric cancer and advanced premalignant lesions and to identify risk factors associated with a worse endoscopic outcome. Methods: This retrospective observational study involving AIG patients undergoing endoscopic surveillance (2006–2024) at the Hospital Clínic de Barcelona. Patients with AIG were identified based on the presence of anti-parietal cell antibodies and/or intrinsic factor antibodies and underwent endoscopic surveillance with histological assessment. Clinical, serological, endoscopic, and histological data were evaluated to estimate the prevalence of gastric lesions. Potential risk factors were evaluated using logistic regression. Results: A total of 70 patients met the inclusion criteria (median age 60 years; 60% female). Advanced premalignant findings (high- and low-grade dysplasia) were identified in 15.7% of the patients, while GC was found in 5.7%. Atrophy and intestinal metaplasia were present in 98.6% and 74.3% of patients, respectively. Female sex was independently associated with a lower risk of advanced neoplastic findings (OR = 0.24; 95% CI: 0.06–0.95; p = 0.044), whereas older age at diagnosis was associated with an increased risk (OR = 1.06; 95% CI: 1.00–1.11; p = 0.031). Conclusions: Given the high prevalence of premalignant lesions in AIG, endoscopic surveillance appears essential for early detection. The observed associations with female sex and older age, toward lower and higher probabilities of advanced neoplastic findings, respectively, may contribute to future risk stratification models. However, the limited identification of significant predictors underlines the complexity of AIG progression and supports the development of individualized follow-up protocols.