Biological Determinants of Peritoneal Dialysis

This study will comprise of patient populations from pre-existing biorepositories and prospectively enrolled subjects. DNA will be analyzed from cohorts with data and DNA already collected and available, while prospective sites will collect plasma, DNA, and spent dialysate for further analysis. Clinical data related to the subjects' first ever Peritoneal Equilibrium Test (PET), demographic information, change in ultrafiltration capacity over time, will be correlated with various genetic markers of interest. Blood and dialysate will be collected at the first study visit, and there will be no additional sample collection. These samples will be collected as part of a PET during a standard of care study visit, or during a timed 4 hour dwell of 2.5% or 4.25% dextrose solution. Annually, subjects will either undergo a PET as standard of care or perform an additional 4 hour dwell as part of the study. These subsequent measures will be utilized to determine change in ultrafiltration capacity over time. This study has two specific aims: Aim 1: To identify and validate genetic loci that influence the peritoneal solute transfer rate (PSTR) at start of PD. Aim 2: To identify and validate genetic loci in pre-specified biologic pathways with change in peritoneal ultrafiltration capacity. If subjects grant permission, Genome Wide Association Studies (GWAS) results may be transferred to the NIH database of genotypes and phenotypes (dbGaP). Additionally, subjects may agree that remaining samples will be maintained at the University of Washington Kidney Research Institute in a repository for use in future research studies.