The Correction of Hemoglobin and Outcomes in Renal Insufficiency (CHOIR) study of 2006 randomized 1,432 CKD patients to target Hb levels of 13.5 g/dL vs. 11.3 g/dL with epoetin alfa treatment (Singh et al., 2006). This evidence concerns the gene GSTM1 and Renal insufficiency.