Peritoneal Transport and Ultrafiltration

A high peritoneal transport status has been associated with a poorer outcome on peritoneal dialysis (PD) patients, but not necessarily PD-dependent conditions are the cause. Our aim has been to analyze the influence that baseline peritoneal small solute transport and ultrafiltration (UF) capacity have on patient and technique survival, after adjusting for comorbid conditions. A secondary objective was to analyze whether the high transport situation is a true marker of comorbidity. We studied 410 patients starting PD. Data at baseline were collected and used to define comorbidity and tally the Charlson index. At baseline, we determined the mass transfer coefficients (MTAC) of urea and creatinine, net UF, plasma albumin levels, and residual renal function (RRF). The mean time on follow-up was 33±28 months. Dropouts during the study were due to renal transplantation in 140 cases; death in 142 cases, and transfer to hemodialysis in 77 cases. Patients with inherent UF deficiency and/or high transport rate showed no significant differences in the survival analysis (patient/technique) when compared to the rest. In Cox hazards analysis only age, Charlson index, and a lower RRF were significant mortality risk factors. None of the studied parameters was a predictor of technique failure. High transporter patients show less plasma albumin levels and UF capacity, higher incidence of comorbidity and liver diseases than the other patients. Moderate to severe liver disease (n=14) is significantly associated with the inherent high transport status, but it is never accompanied by UF failure (UFF). UFF patients show higher RRF, creatinine MTAC, and age. In conclusion, neither the high transport status nor the status of inherent UFF have any influence on patient and technique survival. The inherent high small solute transport status is associated with hypoalbuminemia and greater comorbidity index. The Charlson index, age, and lower RRF are the independent predictors for mortality.