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LEARNING OBJECTIVES
Upon completion of the chapter, the reader will be able to:
Discuss common causes of anemia.
Identify common signs and symptoms of anemia.
Describe diagnostic evaluation required to determine the etiology of anemia.
Develop a treatment regimen considering the underlying cause and patient-specific variables.
Compare and contrast oral and parenteral iron preparations.
Explain the optimal use of folic acid and vitamin B12 in patients with macrocytic anemia.
Evaluate the proper use of epoetin and darbepoetin in patients with anemia caused by cancer chemotherapy or chronic kidney disease.
Develop a plan to monitor the outcomes of pharmacotherapy for the treatment of anemia.
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Anemia is a deficiency of erythrocytes with a corresponding reduction in the concentration of hemoglobin (Hgb) that results in reduced oxygen-carrying capacity of the blood. Some patients with anemia may be asymptomatic initially, but eventually, the lack of oxygen to tissues results in fatigue, lethargy, shortness of breath, headache, edema, and tachycardia. Common causes include acute or chronic blood loss, decreased functional red blood cell (RBC) production, and increased RBC destruction. Determination of the underlying cause of anemia is essential for successful management.
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EPIDEMIOLOGY AND ETIOLOGY
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Anemia is a common diagnosis with a prevalence that varies widely based on age, gender, race/ethnicity, and geographic location (Table 69–1).1,2 As per the World Health Organization, anemia is a serious global issue affecting up to 42% of young children (< 5 years old) and 40% of pregnant women. Patients with specific comorbidities such as cancer and chronic kidney disease (CKD) also have a significantly higher rate of anemia. The incidence of anemia in cancer patients ranges from 30% to 90%. Contributing factors include the underlying malignancy and myelosuppressive antineoplastic therapy.3 The prevalence of anemia in patients with CKD ranges from 15% to 20% in stages 1 through 3 and up to 70% in stage 5.4
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A decrease in erythrocyte production can be multifactorial. One common cause is nutritional deficiencies (iron, vitamin B12, and folic acid) that are often easily treatable and most commonly seen in up to a third of elderly patients.5 Women of childbearing potential are also another group that is at risk of iron deficiency anemia (IDA), given poor dietary intake or iron loss through monthly menstrual cycles. Patients with cancer or CKD generally have dysregulations in iron and erythropoietin (EPO) hemostasis leading to a risk of developing anemia. Patients with chronic immune-related diseases such as rheumatoid arthritis and systemic lupus erythematosus are ...