GSTM1 and chronic kidney disease: This result is in line with that of a previous study of DA in 39 children aged 11–18 years in which most patients achieved stable Hb concentrations after 6 months, whether they had switched to DA from rHuEpo or were ESA-naive [19], and with the results of two Japanese studies in children aged 1–18 years with CKD who switched from rHuEpo or were ESA-naive [15, 16].