What is the best treatment approach for anemia in an older adult?

Treatment of Anemia in Older Adults

Start with oral iron supplementation at one tablet daily of ferrous sulfate, fumarate, or gluconate, while simultaneously investigating the underlying cause, as iron deficiency in the elderly is common and often multifactorial, requiring both treatment and diagnostic workup. 1

Initial Diagnostic Approach

Confirm iron deficiency before proceeding with investigation or treatment:

• Measure serum ferritin as the single most useful marker, with a threshold of 45 mg/dL indicating iron deficiency in anemic patients 1
• In patients with inflammatory conditions (common in elderly), ferritin up to 100 μg/L may still reflect iron deficiency due to its acute-phase reactant properties 1, 2
• Add transferrin saturation, soluble transferrin receptor, or reticulocyte hemoglobin if ferritin is equivocal or inflammation is suspected 1
• A hemoglobin rise ≥10 g/L within 2 weeks of iron therapy strongly confirms absolute iron deficiency even with equivocal lab results 1

Investigate for underlying causes immediately, as anemia in older adults is rarely from dietary deficiency alone:

• Obtain detailed history focusing on: gastrointestinal symptoms, medications (NSAIDs, anticoagulants), dietary patterns, prior GI or bariatric surgery, chronic diseases (heart failure, kidney disease, inflammatory conditions) 1
• Perform urinalysis or urine microscopy to exclude renal blood loss 1
• Screen for celiac disease serologically (found in 3-5% of iron deficiency anemia cases) 1
• In men and postmenopausal women, gastroscopy and colonoscopy should be first-line GI investigations, as gastrointestinal bleeding from lesions (ulcers, tumors) accounts for 62% of iron deficiency anemia in adults 1

Treatment Algorithm

For uncomplicated iron deficiency anemia without active inflammation:

• Prescribe one tablet daily of ferrous sulfate (200 mg), ferrous fumarate, or ferrous gluconate 1
• If gastrointestinal side effects occur, reduce to one tablet every other day rather than discontinuing—this maintains efficacy while improving tolerability 1, 3
• Do not defer iron replacement while awaiting investigations unless colonoscopy is imminent 1
• Monitor hemoglobin response within 4 weeks; continue treatment for approximately 3 months after hemoglobin normalizes to replenish iron stores 1

Switch to intravenous iron when:

• Active inflammation is present (inflammatory bowel disease, chronic heart failure, chronic kidney disease with functional iron deficiency) 1, 2
• Oral iron is not tolerated despite alternate-day dosing 1
• Inadequate response to oral iron after 4 weeks 1
• Severe anemia requiring rapid hemoglobin increase 3
• Post-bariatric surgery with disrupted duodenal absorption 1

Intravenous iron demonstrates superior efficacy in inflammatory states with an odds ratio of 1.57 for achieving 2.0 g/dL hemoglobin rise and odds ratio of 0.27 for treatment discontinuation compared to oral iron. 2

Special Considerations in Older Adults

Carefully weigh risks versus benefits of invasive investigations:

• In patients with major comorbidities or limited performance status, the risks of endoscopy may outweigh benefits 1
• Consider CT colonography as alternative to colonoscopy in those unsuitable for invasive procedures 1
• Recognize that anemia of chronic disease can mimic iron deficiency anemia—only 11% of fast-track referrals with suspected iron deficiency anemia had confirmed diagnosis 1

Address comorbid conditions that complicate anemia:

• In chronic heart failure with functional iron deficiency (ferritin <100 μg/L or ferritin 100-299 μg/L with transferrin saturation <20%), use intravenous iron as it improves symptoms and quality of life; avoid oral iron due to poor absorption from gut edema 1
• In chronic kidney disease, functional iron deficiency is common; refer to nephrology guidelines for management 1
• In inflammatory bowel disease with active inflammation, use intravenous iron as systemic inflammation blocks oral iron absorption 1

Management of Refractory or Recurrent Cases

If hemoglobin fails to respond adequately or anemia recurs after initial correction:

• Investigate small bowel with capsule endoscopy (preferred) or CT/MR enterography for angioectasias, inflammatory disease, or neoplasms 1
• Investigate renal tract if not already done 1
• After negative capsule endoscopy of acceptable quality, further GI investigation is needed only if ongoing iron deficiency anemia persists despite iron replacement 1
• Consider long-term iron replacement therapy as appropriate strategy when cause is unknown or irreversible 1

Critical Pitfalls to Avoid

Do not assume dietary deficiency as the primary cause in older adults—among men and postmenopausal women, less than 2% have iron deficiency anemia from inadequate intake; chronic disease and gastrointestinal bleeding are far more common 1

Do not use high-dose oral iron regimens—100 mg elemental iron daily is as effective as higher doses (60-120 mg) with fewer side effects 1, 3

Do not overlook inflammation as a barrier to oral iron absorption—in active inflammatory states, oral iron is ineffective regardless of dose due to hepcidin-mediated blockade 1, 2

Do not forget transfusion for symptomatic severe anemia—limited packed red cell transfusion may be required for symptomatic patients, but iron replacement therapy remains necessary post-transfusion 1