GSTM1 and chronic kidney disease: HD: Haemodialysis, PD: Peritoneal Dialysis, CAPD: Continuous Ambulatory Peritoneal Dialysis, SC: Subcutaneous, IV: Intravenous, Hb: Haemoglobin, EPO: Erythropoietin, r-HuEPO: Recombinant Human Erythropoietin, ESRD: End-stage Renal Disease, CKD: Chronic Kidney Disease, QoL: Quality of Life