Five-Year Time Profiles of Clearances of Different Uremic Solutes in Incident Peritoneal Dialysis Patients.

Introduction: Different uremic solutes have varying degrees of clearances owing to different chemical properties and the pathological and physiological changes in the kidneys and peritoneum.

Methods: The 5-year time profiles of renal, peritoneal, and total clearances of creatinine, urea nitrogen (UN), uric acid (UA), trimethylamine n-oxide (TMAO), phosphate, beta-2-microglobulin (β2-MG), interleukin-6 (IL-6), indoxyl sulfate (IS), and p-cresol sulfate (PCS) were investigated in 64 peritoneal dialysis (PD) patients. The patients were divided into an early start and a late start group according to baseline estimated glomerular filtration rate to investigate the effect of dialysis initiation timing on uremic solutes clearances. Patients were also divided into incremental peritoneal dialysis (IPD) and full-dose PD groups to investigate the impact of PD strategy on uremic solutes clearances.

Results: Peritoneal clearances of creatinine, UN, UA, and phosphate increased over time, while the peritoneal clearance of IL-6 showed a downward trend. The peritoneal clearances of TMAO, β2-MG, IS, and PCS did not change significantly. Patients in early start group showed a lower level of variation and a higher average of renal clearances. IPD patients had a higher level of total clearances of uremic solutes than full-dose PD patients in the first 3 years after PD initiation.

Conclusion: In a long-term follow-up period, the peritoneal clearance of water-soluble small solutes increased over time, but that of protein-bound toxins and middle molecules did not. Initiating PD when residual kidney function remains at a relatively high level and performing IPD may better improve the efficiency of PD and help preserve the renal clearances of uremic solutes.