Evidence for optimal hemoglobin targets in chronic kidney disease

Even though anemia occurs frequently in patients with chronic kidney disease and therapeutic options are widely available, the ideal hemoglobin target level is not clearly established. We start from 2 anecdotes and review the evidence in favor of and against higher (>12 g/dL) and normal hemoglobin targets as compared to subnormal or low hemoglobin levels in different subsets of chronic kidney disease (either predialysis or dialysis). Current clinical trials and their systematic reviews have found that higher hemoglobin levels (>12 g/dL) do not significantly impact on patient-level cardiovascular end points including cardiovascular and all-cause mortality. Patients feel better, and enhanced quality of life parameters have been identified in most short-term studies when higher hemoglobin levels are achieved. However, achieving and maintaining higher hemoglobin levels carry the risk of hypertension and vascular access thrombosis in dialysis patients and are costly. In addition, a potential for increased risk of death (or no benefit at most) with higher Hb levels has been found in patients with severe cardiac disease in a larger trial. Benefits of and harm from hemoglobin targets should be carefully weighed, and certainly more, proper studies are needed before higher hemoglobin levels (>12 g/dL) are widely adopted in these high-risk patients.