It results either from the advancement of chronic kidney disease being a consequence of the coexistence of other diseases (e.g., diabetes), whose natural course is associated with progressive nephropathy, or the direct action of the above-mentioned proinflammatory cytokines, which inhibit the expression of erythropoietin and, consequently, impede erythropoiesisin response to hypoxia [38,39]. Here, EPO is linked to chronic kidney disease.