Relationship Between Changes in Brain Natriuretic Peptide Levels After Initiation of Peritoneal Dialysis and Duration of Peritoneal Dialysis Monotherapy: A Retrospective Observational Study

Background Peritoneal dialysis (PD) is an integral modality in renal replacement therapy. However, inadequate fluid volume control is a key reason for PD withdrawal. Brain natriuretic peptide (BNP) is effective for evaluating fluid volume in PD patients. This study investigates whether BNP improvement after PD initiation reflects enhanced fluid control and correlates with longer PD duration. Methods A single-center retrospective observational study analyzed 99 patients who started PD between November 2002 and March 2022. BNP levels at PD initiation (BNP_0M), and 6 months later (BNP_6M) were used to calculate the BNP_6M /BNP_0M ratio. Patients were divided into BNP-improved and unimproved groups. PD duration was analyzed using the Kaplan-Meier method, and withdrawal risk from PD monotherapy was analyzed using a multivariable-adjusted Cox proportional hazards and nonlinear analysis. Results Seventy-one patients met the inclusion criteria, with a median follow-up period of 38 months. Kaplan-Meier analysis showed that the BNP-improved group had significantly longer PD monotherapy (log-rank test, P=0.0258). The Cox model indicated that a higher BNP_6M/BNP_0M ratio increased withdrawal risk from PD monotherapy (P=0.038). In the Poisson regression models, improved BNP levels were associated with continued PD monotherapy. Conclusion Improvement in BNP levels after PD initiation correlates with extended PD monotherapy. Regular BNP monitoring as a fluid volume control marker may contribute to assessing stable PD periods and improving the quality of life of patients.