**3. Epidemiology**

The incidence of ESA hyporesponsiveness in hemodialysis patients differs from one country to another, ranging from 7.3 to 17.6%, with more prevalence compared with patients on peritoneal dialysis. ESA hyporesponsiveness was reported in 12.5% of hemodialysis patients and was strongly associated with higher mortality, iron and ESA use, and lower Hb levels. Around 15% of hemodialysis patients requiring high ESA doses have 50% consumption of total ESA therapy costs [13].
