This seems to be confirmed by two small cases series (n = 67) of ND-CKD with 3–5 patients, where the administration of SI (30 mg elemental iron/day) for 12–18 months resulted in maintained or increased Hb levels, without major increments in ferritin at the end of the study period (final mean ferritin 99–116 ng/mL) (Supplementary Materials, Table S2) [89,90]. Here, GSTM1 is linked to chronic kidney disease.