Furthermore, in a CKD population study including patients at stages 3b-4, the adjusted linear inverse association of the flow-mediated dilatation with hemoglobin (Hb) in a range between 8.5 and 14.5 g/dL, demonstrated that (Hb) per se affects the endothelial function regulation which could likely determine the VV neovascularization [25, 26]. Here, GSTM1 is linked to chronic kidney disease.