Iron deficiency workup reveals high incidence of autoimmune gastritis with parietal cell antibody as reliable screening test

Objective:

Iron deficiency (ID) is a common finding especially in young woman and impacts physical and cognitive function as well as quality of life. Current guidelines recommend only the evaluation of coeliac disease in premenopausal woman. We hypothesize that autoimmune gastritis (AIG) is a common finding in ID.

Design:

We did a retrospective analysis of patients who attended an out-patient clinic specialized for ID. Patients with ferritin < 50 µg/L or transferrin saturation < 15% were included. Laboratory work-up included endomysial antibody and parietal cell antibody (PCA). Endoscopy was recommended if antibody were positive. PH of gastric juice was measured during gastroscopy. Histologic slides were evaluated by a routine pathologist and an expert pathologist.

Results:

We included 409 patients with ID, about half of patients were anemic. Patients were predominately female with a median age of 39. Elevated levels of PCA were found in 72 (18.5%) patients. Gastroscopy was performed in 28 patients, in 9 (32.1%) the diagnosis of AIG was confirmed primarily, all had PCA levels > 100U/mL. Re-evaluation of an expert pathologist increased the number of AIG to 13 and three additional patients diagnosed as early/questionable AIG. A sensitivity of 94% and a specificity of 98% was estimated for a PCA cut-off of 100U/mL. Achlorhydria was found in 8 patients, all with AIG. Coeliac disease was found in four (1%) patients.

Conclusion:

AIG is a common finding in patients with ID. PCA are a highly sensitive and specific tool for diagnosis of AIG. Histological scores are needed especially in earlier stages. We conclude that PCA should be included in the non-invasive work up of iron deficiency as undiagnosed AIG may lead to serious complication including pernicious anemia, neuroendocrine tumors, and gastric adenocarcinoma.

No conflict of interest has been declared by the author(s).