Anemia treatment in CKD

Anemia, which is defined as hemoglobin (Hb) concentration <13 g/dL for men and <12 g/dL for women, is a common feature of chronic kidney disease (CKD). The more severe the CKD, the greater is the risk of anemia, so that up to two thirds of patients with end-stage kidney disease are anemic. 

The kidneys are essential to the regulation of red-cell production and thereby maintenance of normal Hb concentration because the hormone erythropoietin, which regulates red-cell production, is synthesized in the kidneys. The usually normochromic, normocytic anemia associated with CKD is the result of erythropoietin deficiency. 

Since the 1980s synthetic erythropoietin preparations, now collectively called Erythropoietin Stimulating Agents (ESA), have been prescribed to correct anemia in patients with CKD. By many measures, this anemia correction leads to improved quality of life for patients with CKD. 

The use of ESA also avoids the necessity for blood transfusion and its associated risks. Despite these positive effects, use of ESA is not without controversy. In a recently published review article the authors explain the controversy and discuss the evidence base that informs the medical communities’ current more cautious approach to prescribing ESA for patients with CKD. 

The controversy, which arose out of concern that ESAs may increase the risk of cardiovascular disease (hypertension stroke, myocardial infarction, etc.) and possibly speed cancer progression, hinges on the degree to which anemia should be corrected. Should patients be treated to a normal Hb target (around 13 g/dL) or is a lesser target (around 11 g/dL) safer in terms of cardiovascular risk? 

Description and discussion of three recently reported randomized controlled clinical trials of ESA, designed to specifically address this question, is the major focus of the article. 

The authors conclude that data from these trials suggests the target Hb should be no higher than 10-12 g/dL. The increased ESA use that would be required to achieve a higher, normal Hb in CKD patients could result in life-threatening cardiovascular disease for a largely unpredictable minority.