The deadly triangle of anemia, renal insufficiency, and cardiovascular disease: implications for prognosis and treatment.

Recently there has been considerable interest in the associations between blood hemoglobin (Hb) level, renal function, and cardiovascular disease. Anemia is a common feature of end-stage renal disease, but it also accompanies lesser degrees of chronic kidney disease (CKD). The degree of anemia roughly approximates the severity of CKD. Anemia seen in diabetes has been linked to diabetic nephropathy; however, diabetes itself affects the hematologic system in several ways. Anemia is associated with left ventricular hypertrophy, cardiovascular morbidity, progressive loss of kidney function, and poor quality of life. Anemia seems to act as a mortality multiplier; that is, at every decrease in Hb below 12 g/dL, mortality increases in patients with CKD, cardiovascular disease, and those with both. Unlike blood transfusion, treatment of anemia with exogenous erythropoietin in patients with cardiorenal disease has shown promise in reducing morbidity and in improving survival and quality of life. Increasing the Hb level from less than 10 g/dL to 12 g/dL has resulted in favorable changes in left ventricular remodeling, improved ejection fraction, improved functional classification, and higher levels of peak oxygen consumption with exercise testing. Clinical trials are underway to test the role of erythropoietin in patients with CKD and in patients with heart failure.