It included 603 CKD stages 3b–4 patients with mild to moderate anemia (defined as Hb between 110 and 125 g/L) and also randomized them into groups with a higher or a lower treatment target (130–150 g/L vs. 105–115 g/L) with a study duration of 3 years. This evidence concerns the gene GSTM1 and anemia.