GSTM1 and chronic kidney disease: HD: Haemodialysis, SC: Subcutaneous, IV: Intravenous, Hb: Haemoglobin, EPO: Erythropoietin, rHuEPO: Recombinant Human Erythropoietin, ESRD: End-stage Renal Disease, rcEPO: Recombinant Human Erythropoietin, t1/2: drug half-life, ESA: Erythropoiesis Stimulating Agent