Peritoneal Total Protein Transport Assessed from Peritoneal Equilibration Tests Using Different Dialysate Glucose Concentrations

Abstract

Background

The peritoneal equilibration test (PET) permits assessment of peritoneal protein transport, but this potential marker of outcome in peritoneal dialysis (PD) patients lacks adequate standardization.

Objectives

To assess various approaches for estimation of peritoneal protein transport in PD patients during 2.27% and 3.86% glucose-based PETs, and to uncover the demographic, clinical, and biochemical correlates of this phenomenon.

Patients and Methods

We studied 90 PD patients who underwent 2.27% and 3.86% PETs in random order, and we used multivariate analysis to compare assessments of peritoneal protein transport in both tests, searching for correlations between D_240′ – D_0′ protein concentration (PETΔPConc), total peritoneal protein excretion (PET-PPE), or total protein clearance (PET-PC) on the one hand (the main study variables), and PET-derived markers of peritoneal function and selected demographic, clinical, and biochemical variables on the other.

Results

The PETΔPConc was higher during the 2.27% PET (mean: 45.2 mg/dL vs 37.0 mg/dL for the 3.86% test; p = 0.003); the PET-PPE and PET-PC were comparable (1121.8 mg vs 1168.9 mg, p = 0.52, and 17.1 mL vs 17.8 mL, p = 0.66, respectively). All three variables sustained a significant, yet moderate correlation (all r² values < 0.30) with the 24-hour PPE rate. Multivariate analysis identified dialysate-to-plasma ratio (D/P_240′) of creatinine, end-to-initial dialysate ratio (D_240′/D_0′) of glucose, current daily peritoneal glucose load, ultrafiltration during PET, systolic blood pressure, and previous cardiovascular events (3.86% test only) as independent predictors of protein transport during PET.

Conclusions

Either PET-PPE or PET-PC seems preferable to PETΔPConc for characterization of peritoneal protein transport. Small-solute transport characteristics, ultrafiltration, and current peritoneal glucose load sustain independent correlations with peritoneal protein transport. The latter variable shows also a moderate association with markers of cardiovascular disease in PD patients.