['Among lipid abnormalities observed in patients with chronic kidney disease (CKD) is a significant decrease in serum high-density lipoprotein cholesterol (HDL-C) levels. In a previously published randomized control trial, we showed that early erythropoietin (EPO) administration in a predialysis population slowed the progression of CKD. In the present nested substudy, we examine whether EPO has an influence on serum HDL-C levels in comparison to other lipid parameters in this population.', 'Eighty-eight patients with CKD stages 3 and 4 were enrolled in the study. Forty-five patients (group 1) were treated with EPO (50 U/kg/wk), targeting to increase hemoglobin levels to 13 g/dL or greater (>or=130 g/L). The other patients (group 2) remained without treatment until hemoglobin levels decreased to less than 9 g/dL (<90 g/L). The duration of the study was 12 months.', 'At the end of the study, we observed a statistically significant decrease in serum levels of total cholesterol, low-density lipoprotein cholesterol (LDL-C), and triglycerides in both groups. However, serum HDL-C levels significantly increased in only group 1 (from 42.5 +/- 10.4 to 55.9 +/- 8.1 mg/dL [1.10 +/- 0.27 to 1.45 +/- 0.21 mmol/L]; P < 0.001), whereas they were unchanged in group 2. In addition, a significant decrease in atherogenic LDL-C/HDL-C ratio was observed in only group 1. Importantly, the increase in serum HDL-C levels correlated positively with the increase in hemoglobin values in EPO-treated patients.'] Does long-term treatment with EPO increase serum levels of high-density lipoprotein in patients with CKD?