Fig. 1.

Flowchart showing the selection of patients for this study. Selection criteria: (1) patients who received ESA therapy for at least 3 months before dialysis initiation; (2) patients who had received the same ESA treatment for a period of 6 months before dialysis initiation (or from the initiation of ESA therapy until the dialysis initiation if the patient had been treated with ESA for 3–5 months before dialysis initiation); (3) patients whose blood test results were available for 3 months before dialysis initiation, and who had blood tested on the day of ESA administration; and (4) patients who had not received an erythrocyte transfusion in the 3 months before dialysis initiation. CERA continuous erythropoietin receptor activator, DA darbepoetin-α, ESA erythropoiesis-stimulating agent