Plasma brain natriuretic peptide concentration on assessment of hydration status in hemodialysis patient

Background: Brain natriuretic peptide (BNP) is released into circulation in response to ventricular dilatation and pressure overload. Plasma BNP concentration correlates with left ventricular mass and dysfunction, which is prevalent in hemodialysis (HD) patients. Methods: To evaluate the potential of BNP level for determination of hydration status, we measured inferior vena caval diameter (IVCD) and BNP levels and performed bioimpedance analysis in 49 HD patients. Results: Pre-HD BNP levels remained unchanged after HD. Agreement between IVCD and pre-HD BNP level in overhydration was significant (kappa = 0.304). The area under the receiver operating characteristic (ROC) curve for overhydration was 0.819 for pre-HD BNP level. When extracellular fluid/total-body water (ECF/TBW) ratios of HD patients were compared with those of 723 controls, pre- and post-HD BNP levels were significantly greater in overhydrated patients. The area under the ROC curve for overhydration by ECF/TBW ratio was 0.781 for pre-HD BNP level. However, there was no significance for pre- or post-HD BNP levels on assessment of normohydration or underhydration. Pre-HD BNP level correlated significantly with post-HD BNP level, post-HD diastolic blood pressure, pulse pressure, and ECF/TBW ratio. IVCD correlated significantly with post-HD BNP level. Conclusion: BNP level seems to have a limited potential for assessment of overhydration In HD patients.