Overhydration May Be the Missing Link between Peritoneal Protein Clearance and Mortality

Area of Science:

• Nephrology
• Peritoneal Dialysis
• Fluid Dynamics

Background:

• Peritoneal protein loss (PPL) is linked to mortality in peritoneal dialysis (PD).
• Inflammation and malnutrition were previously assumed causes of PPL.
• Hydrostatic convection's role in microvascular protein transport was often overlooked in PD.

Purpose of the Study:

• To investigate the significance of fluid overload in peritoneal protein clearance (PPCl) among PD patients.
• To explore the relationship between fluid status and protein transport across the peritoneum.

Main Methods:

• Assessed 67 prevalent PD patients using peritoneal equilibration tests and multifrequency bioelectrical impedance analysis (BIA).
• Calculated PPL and PPCl from 24-hour peritoneal effluent samples.
• Utilized univariable and multivariable analyses to identify predictors of PPCl.

Main Results:

• Average PPL was 5.2 g/24 h, higher in continuous PD.
• Significant associations found between PPCl and BIA parameters indicating overhydration.
• Extracellular water excess and higher D/P creatinine independently predicted higher PPCl.

Conclusions:

• Fluid overload strongly correlates with PPCl, supporting hydrostatic pressure-driven convection.
• Peritoneal small solute transport also associates with PPCl.
• Dialysis prescription adjustments focusing on fluid status can mitigate PPCl.