The mean plasma BNP levels in each group were 27.8 ± 34.5 pg/mL (CKD stages 1 and 2), 64.2 ± 76.5 pg/mL (CKD stage 3), 132.2 ± 195.3 pg/mL (CKD stage 4) and 265.3 ± 343.1 pg/mL (CKD stage 5), and 406.2 ± 440.6 pg/mL (CKD stage 5D) (Fig. 1a). Here, NPPB is linked to chronic kidney disease.