How to manage anemia in an elderly patient with normal iron, transferrin, and ferritin levels but low iron saturation?

Management of Anemia in an Elderly Patient with Low Iron Saturation

This patient has functional iron deficiency (iron saturation 17% despite normal ferritin) and requires comprehensive gastrointestinal evaluation to identify occult blood loss, which is the most common cause of iron deficiency anemia in elderly patients. 1

Immediate Diagnostic Priorities

Confirm Iron Deficiency Status

• Iron saturation of 17% (<20%) confirms functional iron deficiency, even with normal ferritin levels 1
• The hemoglobin of 10.3 g/dL meets criteria for anemia requiring investigation in elderly patients 1
• Normal ferritin can be misleading in elderly patients due to concurrent inflammation or chronic disease, which falsely elevates ferritin 1, 2

Mandatory Gastrointestinal Investigation

In elderly patients with confirmed iron deficiency anemia, bidirectional endoscopy (both upper and lower GI tract) should be performed because: 1

• Occult GI blood loss is the most common cause in this population 1
• Colorectal and gastric carcinoma may present asymptomatically with iron deficiency anemia 1
• Dual pathology (bleeding sources in both upper and lower GI tracts) occurs in 1-10% of elderly patients and increases with age 1
• Men with hemoglobin <12 g/dL should be investigated urgently, as lower hemoglobin suggests more serious disease 1

Upper Endoscopy with Specific Testing

• Perform esophagogastroduodenoscopy (EGD) first, as it reveals pathology in 30-50% of cases 1
• Obtain duodenal biopsies during endoscopy, as 2-3% of iron deficiency anemia patients have celiac disease 1
• Test for Helicobacter pylori infection, a common cause of iron deficiency anemia 2
• Check celiac serology (tissue transglutaminase antibody) if not already done 1

Lower GI Evaluation

• Proceed with colonoscopy even if upper endoscopy identifies pathology, unless carcinoma or celiac disease is found 1
• Consider CT colonography as an alternative in frail elderly patients with significant comorbidities 1

Critical History and Medication Review

Medication Assessment

• Document use of NSAIDs, aspirin, and anticoagulants - these are common causes of iron deficiency anemia in elderly patients 1
• Stop NSAIDs whenever possible 1
• Presence of these medications should not deter investigation 1

Additional Evaluation

• Assess for chronic kidney disease (check serum creatinine and GFR), as this contributes to anemia in elderly patients 1
• Evaluate for chronic inflammatory conditions that may cause functional iron deficiency 1
• Check vitamin B12 and folate levels, as combined deficiencies are common in elderly patients and may mask microcytosis 1, 3

Iron Replacement Strategy

Initial Treatment Approach

While awaiting or conducting investigations, initiate iron supplementation: 2

• Oral iron is first-line therapy: Provide every-other-day dosing to improve absorption and reduce adverse effects 2
• Intravenous iron should be considered if:
  • Patient cannot tolerate oral iron (50% have decreased adherence due to GI side effects) 2
  • No adequate response after 2-4 weeks of oral therapy 2
  • Functional iron deficiency with transferrin saturation <20% and ferritin <800 ng/mL 1

Monitoring Response

• Reassess hemoglobin and iron studies in 2-4 weeks 2
• If hemoglobin does not increase after 4 weeks of oral iron, proceed to intravenous iron 1

Important Caveats

Risk Stratification in Elderly Patients

• Carefully weigh risks and benefits of invasive endoscopy in patients with major comorbidities, limited performance status, or frailty 1
• Discuss investigation options with the patient and family, considering their preferences and life expectancy 1
• Even mild anemia (hemoglobin >10 g/dL) in elderly patients is associated with worsening physical performance, cognitive function, and frailty 1, 4

When to Refer to Hematology

• If no GI source is identified despite thorough investigation 5
• If anemia persists despite adequate iron replacement 5
• Consider myelodysplastic syndrome or other bone marrow disorders in unexplained cases 4, 3

Transfusion Considerations

• Maintain hemoglobin threshold of 9-10 g/dL in stable elderly patients 5
• Transfuse for symptomatic anemia (tachycardia, tachypnea, postural hypotension) to maintain hemoglobin 8-10 g/dL 1