Hemoglobin targets for the anemia of chronic kidney disease: a meta-analysis of randomized, controlled trials

Anemia affects almost all patients with chronic kidney disease (CKD), reduces quality of life, and is a risk factor for early death. Higher hemoglobin (Hb) targets have been widely advocated because of data from observational studies showing that higher Hb is associated with improved survival and quality of life, but higher Hb targets may cause access thrombosis and hypertension and are costly. This study aimed to evaluate the benefits and harms of different Hb targets in CKD on the basis of randomized trial evidence. A comprehensive search of the Cochrane Trials Registry, Medline, Embase, and reference lists was performed. Two independent reviewers assessed studies for inclusion criteria and extracted data on all-cause mortality, cardiovascular disease, strokes, hypertension, seizures, hyperkalemia, access thrombosis, and quality of life. Analysis was by a random-effects model, and results are expressed as relative risk (RR) or weighted mean difference with 95% confidence intervals (CI). Nineteen relevant trials were identified. Twelve trials (638 patients) compared use of erythropoietin versus no erythropoietin treatment, and seven trials (2058 patients) compared higher versus lower Hb targets. Compared with Hb values of >130 g/L or more in the CKD population with cardiovascular disease, Hb values of <120 g/L were associated with lower all-cause mortality (RR, 0.84; 95% CI, 0.71 to 1.00). Hb values of 100 g/L or less reduced the risk of hypertension (RR, 0.50; 95% CI, 0.33 to 0.76) but increased the risk of seizures (RR, 5.25; 95% CI, 1.13 to 24.34). From the available trial evidence, in CKD patients with cardiovascular disease, the benefits associated with higher Hb targets (reduced seizures) are outweighed by the harms (increased risk of hypertension and death). There is insufficient data to guide decisions in patients without cardiovascular disease or in the predialysis population.