Jan

13

2025

Vitamin B12 Deficiency in Patients with Iron Deficiency

By William Aird

  • Autoimmune atrophic gastritis (AAG) leads to hypochlorhydria or achlorhydria due to destruction of parietal cells in the gastric body, potentially interfering with absorption of oral iron and subsequent IDA.
  • About 20% of patients with iron deficiency anemia without an obvious cause have evidence of pernicious anemia/AAG (low B12, positive anti-parietal cell/IF antibodies, and/or gastric biopsy).
  • While the AGA Clinical Practice Guidelines on the GI Evaluation of IDA recommends against routine w/u for AAG in patients with ID, it seems reasonable to screen those patients with unexplained ID.
  • Lenti et al said it well: “Patients with unexplained iron deficiency anemia or those with refractory iron deficiency anemia (that is, those who do not respond to iron supplementation) should be investigated for AIG [AAG]”1