Fig. 1

Flow diagram of patient selection. In the Total cohort, patients undergoing PD with available data on ESA dose and residual urine were included to examine the association between urine output and ERI. In the Analytic cohort, after excluding those with a urine volume ≤ 100 mL/day at baseline and those with only one urine data available, we examined the longitudinal association of ERI with urine output. PD, peritoneal dialysis; ESA, erythropoiesis-stimulating agent; ERI, ESA resistance index; UV, urine volume.