Abstract: Objective  To explore the mechanism of relative erythrocytosis in hemodialysis patients. Methods   Patients on chronic hemodialysis were divided into subgroups according  to the baseline hemoglobin levels and whether they treated with erythropoiesis stimulating agent (ESA). Clinical characteristics and laboratory data was collected at baseline. The degree of anemia, hyperparathyroidism, and iron metabolism were compared between the two groups. All patients were followed up for 84 months.  Results   In total, 161 patients were enrolled. Fourteen (8.7%) were diagnosed as relative erythrocytosis, with significantly higher level of hemoglobin compared to ESA treated group [(130.8±13.3) vs. (110.3±11.8)g/L, t=6.108, P＜0.001]. The level of hepcidin was significantly lower in patients without ESA treatment [(5.33±5.21) vs. (20.07±10.17)×104 pg/ml, t=-4.857, P＜0.001). And in both of groups, there was a negative correlation between hepcidin level and hemoglobin concentration (r=-0.491, P=0.007). The level of hepcidin positively correlated with ferritin (r=0.684, P＜0.001) and negatively correlated with the level of soluble transferrin receptor (sTfR,    r=-0.406, P=0.029). There was no association between hepcidin and proinflammatory cytokines.  Conclusion   A small portion of hemodialysis patients may maintain reasonable activity of erythropoiesis with no need of treatment with ESA or supplement of iron. They show a relatively lower level of circulating hepcidin than patients treated with ESA. And the higher the level of hepcidin, the less iron available for the tissue, and the lower activity of erythropoiesis.

Key words: Hemodialysis, Relative erythrocytosis, Hepcidin, Inflammation