Biological Determinants of Peritoneal Dialysis

Study Overview
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Brief Summary
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Peritoneal Dialysis (PD) is a technique for treating kidney failure where fluid is instilled into the body's peritoneal cavity. Fluid and solutes travel across the peritoneal membrane, and the function of this membrane is critical to successful PD. Studies have shown that certain demographic and clinical variables explain a very small part of the variability in baseline function. This study will further explore the common genetic variants that determine the baseline peritoneal membrane function in patients starting treatment with PD and change in function upon treatment . This study will incorporate data from subjects' first ever peritoneal equilibrium test (PET), changes in the transfer of water across the peritoneal membrane over time, demographic information, and results from laboratory analysis of DNA, blood, and dialysate. The investigators hope that this study will provide information on the biological pathways that account for variability in the peritoneal membrane. This could ultimately lead to the development of biomarkers to identifying individuals at risk for decline in peritoneal membrane function over time and/or be used to identify novel therapeutic targets to preserve or enhance membrane function. Identifying the biological pathways will also increase the understanding of vascular biology, angiogenesis, and fibrosis that could be applied to other tissues and other diseases.

Detailed Description
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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.

Official Title
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Biological Determinants of Peritoneal Dialysis

Conditions
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End-Stage Kidney Disease

Intervention / Treatment
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* Other: Peritoneal Equilibrium Test
* Other: 4 hour dwell of 2.5/4.25% dextrose solution


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adults over the age of 20 who are able to provide consent Record of a PET within 6 months of starting PD treatment Exclusion Criteria: None

Ages Eligible for Study
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Minimum Age: 20 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Discovery for Aim One<br>2173 subjects will be involved in the discovery cohort. | Other: Peritoneal Equilibrium Test<br>* These will be done as part of standard of care procedures. PETs will not be performed solely for research purposes.<br>Other: 4 hour dwell of 2.5/4.25% dextrose solution<br>* If a PET is not performed annually as part of standard of care, subjects will undergo a 4 hour timed dwell with either 2.5 or 4.25% dextrose solution. This will be for the purposes of sample collection and/or measurement of ultrafiltration capacity.<br>|
| Replication for Aim One<br>1673 subjects will comprise the replication cohort. | Other: Peritoneal Equilibrium Test<br>* These will be done as part of standard of care procedures. PETs will not be performed solely for research purposes.<br>Other: 4 hour dwell of 2.5/4.25% dextrose solution<br>* If a PET is not performed annually as part of standard of care, subjects will undergo a 4 hour timed dwell with either 2.5 or 4.25% dextrose solution. This will be for the purposes of sample collection and/or measurement of ultrafiltration capacity.<br>|
| Discovery for Aim Two<br>824 subjects will be involved in the discovery cohort. | Other: Peritoneal Equilibrium Test<br>* These will be done as part of standard of care procedures. PETs will not be performed solely for research purposes.<br>Other: 4 hour dwell of 2.5/4.25% dextrose solution<br>* If a PET is not performed annually as part of standard of care, subjects will undergo a 4 hour timed dwell with either 2.5 or 4.25% dextrose solution. This will be for the purposes of sample collection and/or measurement of ultrafiltration capacity.<br>|
| Replication for Aim Two<br>538 subjects will comprise the replication cohort. | Other: Peritoneal Equilibrium Test<br>* These will be done as part of standard of care procedures. PETs will not be performed solely for research purposes.<br>Other: 4 hour dwell of 2.5/4.25% dextrose solution<br>* If a PET is not performed annually as part of standard of care, subjects will undergo a 4 hour timed dwell with either 2.5 or 4.25% dextrose solution. This will be for the purposes of sample collection and/or measurement of ultrafiltration capacity.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Four-hour Dialysate to Plasma ratio of creatinine | From Peritoneal Equilibration Test performed at the time of start of PD | Prior to study participation or within 6 months of enrollment | 
| Change in peritoneal ultrafiltration capacity over time | This will be determined from annual assessments of the peritoneal ultrafiltration capacity with a four-hour timed dwell with 4.25%/2.5% dextrose. | Once per year (up to 3 years) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Peritoneal Dialysis, Genetic, Peritoneal Membrane, Peritoneal Equilibrium Test, Ultrafiltration Capacity, End Stage Renal Disease (ESRD)