Anemia is more common in patients with heart disease. It is present in approximately one third of patients with congestive heart failure (CHF) and 10% to 20% of patients with coronary heart disease (CHD). The cause of anemia in heart disease is not fully understood. Several factors probably contribute, including iron deficiency, comorbid chronic kidney disease, blunted erythropoietin production, hemodilution, aspirin-induced gastrointestinal blood loss, use of renin–angiotensin–aldosterone system blockers, cytokine-mediated inflammation (anemia of chronic disease), and gut malabsorption with consequent nutritional deficiency.