What are the common causes of anemia in the elderly?

Common Causes of Anemia in the Elderly

Iron deficiency is a major contributory factor in about half of anemia cases in the elderly, often occurring alongside other deficiencies and causes. 1

Primary Causes

• Iron deficiency is present in approximately one-third of elderly patients with anemia, requiring thorough investigation due to potential underlying gastrointestinal malignancy 1, 2
• Chronic inflammation and chronic kidney disease account for another third of anemia cases in the elderly population 3, 1
• Unexplained anemia comprises the remaining third of cases, despite thorough investigation 4, 3
• Multiple nutritional deficiencies often coexist, with vitamin B12 and folate deficiencies frequently accompanying iron deficiency 1, 5

Iron Deficiency Causes in the Elderly

• Poor dietary intake is common in elderly patients, particularly those with decreased appetite or limited access to iron-rich foods 1, 5
• Reduced iron absorption occurs with aging and is exacerbated by medications like proton pump inhibitors 1
• Occult blood loss from gastrointestinal tract, particularly from malignancies, requires thorough investigation 1
• Medication effects, especially from aspirin and other antiplatelet/anticoagulant therapies that increase risk of GI bleeding 1
• Chronic disease states such as chronic kidney disease (CKD) and chronic heart failure (CHF) contribute to functional iron deficiency 1

Chronic Disease-Related Anemia

• Chronic kidney disease causes anemia when GFR falls below 60 mL/min/1.73m², with increasing prevalence as renal function deteriorates 1

  • Multiple mechanisms contribute including reduced erythropoietin production, iron deficiency, and reduced red cell survival 1
  • Functional iron deficiency in CKD is defined as transferrin saturation ≤20% with serum ferritin ≤100 μg/L (predialysis) or ≤200 μg/L (hemodialysis) 1

• Chronic heart failure is associated with iron deficiency in 40-70% of cases 1

  • Causes include malabsorption, malnutrition, GI blood loss, and increased hepcidin release from chronic inflammation 1
  • Defined as serum ferritin <100 μg/L and/or transferrin saturation <20% 1

Other Important Causes

• Inflammatory conditions increase hepcidin production, reducing iron absorption and mobilization from stores 1, 5
• Vitamin B12 deficiency can cause macrocytic anemia and may coexist with iron deficiency 6, 7
• Riboflavin deficiency can interfere with iron handling and contribute to anemia when iron intake is low 1
• Malabsorption disorders such as celiac disease can lead to multiple nutritional deficiencies 1
• Protein-energy malnutrition stimulates increased cytokine production, leading to inflammation and anemia 5

Clinical Impact

• Anemia in older adults is associated with increased mortality risk, even when mild 2, 4
• Contributes to worsening physical performance, cognitive function, and frailty 1, 8
• Associated with increased risk of falls, fractures, and loss of independent functioning 8, 4
• Often underdiagnosed and undertreated despite significant impact on quality of life 8

Diagnostic Approach

• Measure serum ferritin and transferrin saturation to confirm iron deficiency 1, 2
• Consider that inflammatory conditions may elevate ferritin despite iron deficiency 1, 6
• Evaluate both upper and lower GI tract in elderly patients with confirmed iron deficiency anemia to exclude malignancy 1
• Consider CT colonography as an alternative to colonoscopy in frail elderly patients 1
• Assess for vitamin B12 and folate deficiency, particularly when macrocytosis is present 6, 4

Treatment Considerations

• Treat underlying causes when identified 2, 4
• Oral iron remains first-line treatment for iron deficiency in most elderly patients 1, 2
• Consider parenteral iron when oral iron is not tolerated or ineffective, particularly in heart failure 1, 2
• Ensure adequate protein intake (minimum 1.7g/kg/day) and caloric intake (minimum 1700 kcal/day) to maintain anabolism and reduce inflammation 5
• Carefully weigh risks and benefits of invasive investigations in frail elderly patients with limited life expectancy 1

Remember that anemia in the elderly is often multifactorial, and a thorough evaluation is necessary to identify all contributing causes 1, 3.