Objective: To clarify the association of brain natriuretic peptide * BNP) with renal function and cardiac dysfunction in non-dialysis-dependent patients with chronic kidney disease (CKD).
Methods: Fluorescence immuno-assay was used to detect the whole blood concentration of BNP in a cohort of 203 CKD patients and 16 hypertensive controls. Color ultrasonography was conducted to determine the left ventricular mass index (LVMI). Estimated glomerular filtration rate (eGFR) was examined. The relationship of BNP to eGFR and LVMI in these patients.
Results: There was a trend that the BNP level increased with the decrease of the level of eGFR [9.35 (7.35-15.00) vs 54.40 (15.10-173.00) ng/L, P < 0.01]. Spearman correlation showed that BNP level was correlated negatively with eGFR (r = -0.417, P < 0.01). Multiple regression analysis showed that eGFR was the independent determinant of BNP (beta = -0. 293, P < 0.01), and lgBNP concentration increased by 0.293 ng/L per 1 ml x min(-1) x (1.73 m2)(-1) reduction in lgGFR. The incidence of LV hypertrophy was much higher in the CKD patients than in the controls (53.2% vs 10.0%, P < 0.05). BNP level was greater in the patients with LV hypertrophy [93.05 (37.70-272.00) vs 17.30 (7.20-63.70) ng/L, P < 0.01], and LVMI had an independent effect on BNP concentration ( beta = 0.266, P < 0.01). lgBNP level increased by 0.266 ng/L per 1 g/m2 increase in lgLVMI.
Conclusion: The declining eGFR level independently elevates the BNP level in non-dialysis-dependent CKD patients. Although renal dysfunction itself may affects the BNP concentration, LV hypertrophy is a powerful independent determinant of BNP.