Levin et al. [20] studied 175 patients with CKD, who had an endogenous creatinine clearance rate of 25.5 ± 17 mL/min; consistent with the results of the present study, they found that for every 10 g/L drop in Hb, the risk of CVD increased by 6%. This evidence concerns the gene GSTM1 and chronic kidney disease.