Brain natriuretic peptide variations are linked to volume status in hemodialysis patients

Aims: To evaluate the usefulness of monthly brain natriuretic peptide (BNP) dosage in assessing dry weight in hemodialysis patients. Patients and methods: Over a 2-year period, we performed in 46 hemodialysis patients monthly BNP level measurements, and adapted dry weight following the determination of variations in BNP concentrations for each month during the study period. Then we tested our approach by looking for a statistical relation between monthly alterations in BNP levels and monthly variations in the patients' weight, blood pressure, hemoglobinemia and albuminemia which are in themselves related to fluid status variations. Results: Monthly BNP level variations were found to be positively correlated with monthly end-dialysis weight alterations (r = +0.24, p < 0.001), with monthly systolic and diastolic blood pressure variations before dialysis (r = +0.09, p < 0.001; r = +0.24, p < 0.001), and with systolic and diastolic blood pressure changes after dialysis (r = +0.09, p = 0.001; r = +0.25, p < 0.001). Moreover, monthly BNP level variations were negatively correlated with monthly hemoglobinemia changes (r = -0.17, p = 0.004) and with monthly albuminemia alterations (r = -0.14, p = 0.001). Conclusion: In a non-selected population of hemodialysis patients it was found that monthly BNP level variations were positively correlated with monthly volume status alterations as evaluated by clinical and biological criteria. BNP appears to be a useful tool for dry weight assessment despite the absence of a standardized cut-off point for BNP levels in hemodialysis patients.