Context: Autoimmune gastritis and pernicious anaemia are common autoimmune disorders, being present in up to 2% of the general population. In patients with type 1 diabetes or autoimmune thyroid disease the prevalence is 3- to 5-fold increased. This review addresses the epidemiology, pathogenesis, diagnosis, clinical consequences, and management of autoimmune gastritis in type 1 diabetic patients.

Synthesis: Autoimmune gastritis is characterised by 1) atrophy of the corpus and fundus; 2) autoantibodies to the parietal cell (PCA) and to intrinsic factor, 3) achlorhydria, 4) iron deficiency anaemia, 5) hypergastrinaemia. 6) Pernicious anaemia may result from vitamin B12 deficiency. 7) In up to 10% of patients, autoimmune gastritis may predispose to gastric carcinoid tumours or adenocarcinomas. This provides a strong rationale for screening, early diagnosis and treatment. The management of patients with autoimmune gastritis implies yearly determination of gastrin, iron, vitamin B12 levels, and a complete blood count. Iron or vitamin B12 should be supplemented in patients with iron deficiency or pernicious anaemia. Whether regular gastroscopic surveillance including biopsies is needed in patients with autoimmune gastritis/pernicious anaemia is controversial. The gastric carcinoids that arise in these patients generally do not pose a great threat to life, while the danger of developing carcinoma is controversial. Nevertheless, awaiting a consensus statement, we suggest to perform gastroscopy and biopsy at least once in patients with PCA-positivity, iron- or vitamin B12-deficiency anaemia, or high gastrin levels.

Conclusion: The high prevalence of autoimmune gastritis in type 1 diabetic patients and its possible adverse impact on the health of the patient, provide a strong rationale for screening, early diagnosis, periodic surveillance by gastroscopy, and treatment.