title: Uremic Solutes in Chronic Kidney Disease and Their Role in Progression.
abstract: BACKGROUND
  To date, over 150 possible uremic solutes have been listed, but their role in the progression of CKD is largely unknown. Here, the association between a selected panel of uremic solutes and progression in CKD patients was investigated.
  
  
  METHODS
  Patients from the MASTERPLAN study, a randomized controlled trial in CKD patients with a creatinine clearance between 20 and 70 ml/min per 1.73m2, were selected based on their rate of eGFR decline during the first five years of follow-up. They were categorized as rapid (decline >5 ml/min per year) or slow progressors. Concentrations of eleven uremic solutes were obtained at baseline and after one year of follow-up. Logistic regression was used to compare the odds for rapid to slow progression by uremic solute concentrations at baseline. Variability in uremic solute levels was assessed using scatter plots, and limits of variability were calculated.
  
  
  RESULTS
  In total, 40 rapidly and 40 slowly progressing patients were included. Uremic solutes were elevated in all patients compared to reference values for healthy persons. The serum levels of uremic solutes were not associated with rapid progression. Moreover, we observed substantial variability in solute levels over time.
  
  
  CONCLUSIONS
  Elevated concentrations of uremic solutes measured in this study did not explain differences in rate of eGFR decline in CKD patients, possibly due to lack of power as a result of the small sample size, substantial between patient variability, and variability in solute concentrations over time. The etiology of intra-individual variation in uremic solute levels remains to be elucidated.
authors.affiliation: Department of Nephrology, Radboud Institute of Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Jan A J G
authors.initials: JA
authors.lastname: van den Brand
authors.affiliation: Department of Pharmaceutical Technology and Biopharmacy, University of Groningen, Groningen, The Netherlands.
authors.forename: Henricus A M
authors.initials: HA
authors.lastname: Mutsaers
authors.affiliation: Department of Nephrology and Hypertension, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors.forename: Arjan D
authors.initials: AD
authors.lastname: van Zuilen
authors.affiliation: Department of Nephrology and Hypertension, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Blankestijn
authors.affiliation: Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Petra H
authors.initials: PH
authors.lastname: van den Broek
authors.affiliation: Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Frans G M
authors.initials: FG
authors.lastname: Russel
authors.affiliation: Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht, The Netherlands.
authors.forename: Rosalinde
authors.initials: R
authors.lastname: Masereeuw
authors.affiliation: Department of Nephrology, Radboud Institute of Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Jack F M
authors.initials: JF
authors.lastname: Wetzels
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D002853:Chromatography, Liquid; D003404:Creatinine / Q000097:blood; D018450:Disease Progression; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology; D006801:Humans; D007677:Kidney Function Tests / Q000379:methods*; D008297:Male; D008875:Middle Aged; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000473:pathology*; D053719:Tandem Mass Spectrometry; D014511:Uremia / Q000097:blood*
chemical_list: D003404:Creatinine