Peritoneal total protein transport assessed from peritoneal equilibration tests using different dialysate glucose concentrations

Abstract

[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 D₂₄₀' - D₀' 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/P₂₄₀') of creatinine, end-to-initial dialysate ratio (D₂₄₀'/D₀') 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.