Iron deficiency anemia is a common complication for a patient with inflammatory bowel disease.
Mechanisms for iron deficiency include:
(1) gastrointestinal blood loss, which may be occult, associated with disease activity
(2) poor iron absorption
Criteria for iron deficiency:
(1) serum ferritin concentration < 30 µg/L in the absence of inflammation
(2) serum ferritin concentration < 100 µg/L in the presence of systemic inflammation (serum CRP >= 5 mg/L)
Risk factors for iron deficiency:
(1) menstruation in females
(2) moderate or severe IBD disease activity
(3) decreased available intestinal surface area (fistula, bowel resection, etc)
Cut-offs for anemia are sex-dependent (< 12 g/dL for females; < 13 g/dL for males). These cut-offs may vary.
In patients with inflammatory bowel disease:
(1) it is important to screen for iron deficiency
(2) identify an effective means of iron repletion, with intravenous administration having several benefits
Anemia may be multifactorial, with iron deficiency present along with:
(1) anemia of chronic disease
(2) folate deficiency
(3) vitamin B12 deficiency
(4) hemolytic anemia
(5) drug-induced
