Patients with CKD3b had a higher prevalence of hypertension (96.1% vs. 76.9%, p = 0.002), lower Hb levels (116 ± 15 g/l vs. 122 ± 13 g/l, p < 0.001), and higher plasma NT-proBNP levels (1227.7 ± 1177.8 pg/ml vs. 785.4 ± 752.0 pg/ml, p = 0.021) compared with patients with CKD3a. This evidence concerns the gene GSTM1 and Hypertension.