McMahon et al. undertook a randomized trial of iron sucrose (100–200 mg every two months) or oral iron sulfate for 12 months in patients with ND-CKD who were non-anemic (Hb ≥11 g/dL) and iron replete (ferritin >300 μg/L and TSAT >25%) at baseline, and has described a similar change in eGFR in both treatment groups over the study period [29]. This evidence concerns the gene GSTM1 and chronic kidney disease.