Background: Autoimmune atrophic gastritis (AAG) leads to iron and/or vitamin B12
malabsorption, with subsequent haematological alterations which could represent the sole clinical
manifestation. We aimed to assess patterns of anaemia and micronutrient deficiencies in patients
with AAG at the time of diagnosis. Methods: Observational, multicentre, cross-sectional study
including consecutive adult patients diagnosed with AAG within the last ten years. Cell blood count,
red cell distribution width, serum vitamin B12, and ferritin were collected. Multivariate analysis for
predictive factors of anaemia was computed. Results: 654 AAG patients (mean age 59.2 ± 13.8 years,
female (F): male (M) ratio = 2.3:1) were included. Anaemia was present in 316 patients (48.3%; mean age
60.1 ± 15.8 years, F:M ratio=2.3:1). Pernicious anaemia (132/316 cases, 41.7%) wasmore common inmales
(27.1% versus 12.4%; p = 0.001) and in older patients (63.0 ± 14.6 versus 58.9 ± 14.9 years; p = 0.014),
while iron deficiency anaemia (112/316 cases, 35.4%) was more common in females (16.9% versus 10.0%;
p = 0.039) and in younger patients (56.8 ± 16.6 versus 60.2 ± 14.6 years; p = 0.043). The prevalence of iron
deficiency was equally distributed between anaemic and non-anaemic patients (p = 0.9). Anisocytosis
(odds ratio: 10.65, 95% confidence interval: 6.13–18.50, p < 0.0001) was independently associated with
anaemia. Conclusions: Anaemia is a common manifestation in AAG patients, mostly due to micronutrient
deficiencies. Scant haematologic alterations and micronutrient deficiencies may precede overt anaemia.
