What is the approach to treating anemia?

Approach to Anemia

The treatment of anemia should be guided by identifying the underlying cause through appropriate diagnostic workup, followed by targeted therapy that addresses both the etiology and iron replacement when indicated.1

Diagnostic Approach

• Anemia is defined as a reduction in hemoglobin concentration, red-cell count, or packed cell volume below normal levels 1
• Classification by severity:
  • Mild: Hb ≤11.9 g/dl and ≥10 g/dl 1
  • Moderate: Hb ≤9.9 and ≥8.0 g/dl 1
  • Severe: Hb <8.0 g/dl 1

Initial Assessment

• Complete blood count (CBC) with indices to characterize anemia and identify other cytopenias 2
• Visual review of peripheral blood smear to confirm RBC size, shape, and color 2
• Morphologic classification based on mean corpuscular volume (MCV):
  • Microcytic (<80 fL): iron deficiency, thalassemia, anemia of chronic disease 2
  • Normocytic (80-100 fL): hemorrhage, hemolysis, bone marrow failure, chronic inflammation 2
  • Macrocytic (>100 fL): vitamin B12/folate deficiency, alcoholism, MDS 2

Further Evaluation

• Reticulocyte count to assess bone marrow response 2
• Iron studies: serum iron, total iron binding capacity (TIBC), transferrin saturation, ferritin 2
  • Ferritin <15 μg/L indicates absolute iron deficiency 2
  • In inflammatory states, ferritin <100 μg/L with transferrin saturation <16% suggests iron deficiency 2
• Assessment for occult blood loss in stool and urine 1
• Inflammatory markers (ESR, CRP) to identify anemia of chronic disease 2

Treatment Approach

Iron Deficiency Anemia

• Oral iron supplementation is first-line therapy 1
  • Ferrous sulfate 324 mg (65 mg elemental iron) daily or twice daily between meals 1, 3
  • Continue treatment for 2-3 months after hemoglobin normalization to replenish iron stores 1, 4
• Intravenous iron therapy is indicated when:
  • Oral iron is not tolerated due to side effects 5
  • Malabsorption is present 1
  • Rapid repletion is needed 1
  • In inflammatory bowel disease with active inflammation 2

Anemia of Chronic Disease

• Treat the underlying inflammatory condition to enhance iron absorption and reduce iron depletion 2
• In inflammatory bowel disease with iron deficiency anemia and active inflammation, intravenous iron therapy is recommended 2
• Consider erythropoiesis-stimulating agents (ESAs) in specific situations:
  • Not recommended for mild to moderate anemia with heart disease 2
  • May be appropriate for chemotherapy-induced anemia with Hb ≤10 g/dl 1

Transfusion Therapy

• Reserved for severe symptomatic anemia or when rapid correction is needed 1
• Use restrictive red blood cell transfusion strategy (trigger hemoglobin threshold of 7-8 g/dl) in hospitalized patients with coronary heart disease 2, 1
• Packed red cell transfusions indicated when hemoglobin decreases to less than 7.5 g/dl and/or clinical symptoms are present 2

Special Considerations

Inflammatory Bowel Disease

• Determine whether iron deficiency anemia is due to inadequate intake/absorption or loss of iron through gastrointestinal bleeding 2
• Active inflammation should be treated effectively to enhance iron absorption 2
• Intravenous iron therapy should be given in patients with active inflammation and compromised absorption 2

Heart Disease

• Use restrictive red blood cell transfusion strategy (trigger hemoglobin threshold of 7-8 g/dl) 2
• Avoid erythropoiesis-stimulating agents in patients with mild to moderate anemia and congestive heart failure or coronary heart disease 2

Cancer-Related Anemia

• Evaluate for multiple potential causes including chemotherapy effects, nutritional deficiencies, and bone marrow infiltration 2
• Consider ESAs for chemotherapy-induced anemia with appropriate hemoglobin thresholds 1
• Monitor for functional iron deficiency which may limit response to ESAs 2

Monitoring and Follow-up

• For iron deficiency anemia: Repeat hemoglobin measurement after 4 weeks of treatment 1
• Continue iron treatment for 2-3 months after correction of anemia to replenish stores 1, 4
• For other types of anemia: Monitor based on the underlying condition with regular assessment of iron status and hemoglobin levels 1

Common Pitfalls

• Failure to identify and treat the underlying cause leading to recurrence 1, 4
• Not recognizing that ferritin is an acute phase reactant; in inflammatory states, higher ferritin cutoffs (30-100 μg/L) should be used to diagnose iron deficiency 2
• Inadequate duration of iron therapy leading to incomplete replenishment of iron stores 4
• ESAs carry risks including hypertension, thromboembolism, and potential tumor progression in cancer patients 1
• Transfusions should be used judiciously due to associated risks 1