Previous renal replacement therapy time at start of peritoneal dialysis independently impact on peritoneal membrane ultrafiltration failure

Acknowledgments The authors are grateful to Professor Denisa Mendonc¸a for statistical advice, to Dr. Antonio Cabrita, Dr. MJ Carvalho, and nurse Olivia Santos for patient recruitment and management.Abstract Background. Peritoneal membrane changes are induced by uraemia per se. We hypothesise that previous renal replacement therapy (RRT) time and residual renal function (RRF) at start of peritoneal dialysis impact on ultrafiltration failure (UFF). Methods. The time course of PET parameters from 123 incident patients, followed for median 26 (4-105) months, was evaluated by mixed linear model. Glucose 3.86% solutions were not used in their standard therapy. Sex, age, diabetes, previous RRT time, RRF, comorbidity score, PD modality and peritonitis episodes were investigated as possible determinants of UFF-free survival. Results. PET parameters remained stable during follow up. CA125 decreased significantly. Inherent UFF was diagnosed in 8 patients, 5 spontaneously recovering. Acquired UFF group presented type I UFF profile with compromised sodium sieving. At baseline they had lower RRF and longer previous time of RRT which remained significantly associated with UFF-free survival by Cox multivariate analysis (HR 0.648 (0.428-0.980), P = 0.04) and (HR 1.016 (1.004-1.028), P = 0.009, resp.). UFF free survival was 97%, 87% and 83% at 1, 3 and 5 years, respectively. Conclusions. Inherent UFF is often unpredictable but transitory. On the other hand baseline lower RRF and previous RRT time independently impact on ultrafiltration failure free survival. In spite of these detrimental factors generally stable long-term peritoneal transport parameters is achievable with a 5-year cumulative UFF free survival of 83%. This study adds a further argument for a PD-first policy