title: Predictive performance of different kidney function estimation equations in lung transplant patients.
abstract: BACKGROUND
  There has been limited examination of the performance of glomerular filtration rate estimation (eGFR) equations in lung transplant populations. This study aimed to compare the performance of serum creatinine and cystatin C based eGFR equations with Tc-99m diethylenetriaminepentaacetic acid (DTPA) GFR measurements in individuals with end-stage lung disease, either prior to, or following, lung transplantation.
  
  
  METHODS
  In this prospective observational study, participants underwent GFR measurements with Tc-99m Pentetate. Measured results were compared with GFR estimates derived from estimation equations [4-variable Modification of Diet in Renal Disease, Cockcroft-Gault, Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine, cystatin C and creatinine-cystatin C combined equations].
  
  
  RESULTS
  Ninety-seven individuals were studied (77 post- and 20 wait-listed for transplantation). Median (range) radionucleotide GFR was 56.7ml/min/1.73m2(22.8-109.2ml/min/1.73m2). In the study cohort as a whole, the CKD-EPI creatinine-cystatin C combined equation showed the highest performance, but was only slightly superior to the CKD-EPI creatinine equation. However, in individuals with cystic fibrosis, low arm muscle mass and/or low body mass index, all of the creatinine-based equations showed unacceptable performance. In these subgroups, improved GFR estimation was seen with the CKD-EPI cystatin C equation, and predictions were better still using the CKD-EPI creatinine-cystatin C combined equation.
  
  
  CONCLUSIONS
  This study shows adequate predictive ability of CKD-EPI creatinine in the cohort as a whole, but unacceptable performance in patients with cystic fibrosis, low arm muscle mass and/or low body mass index. Our findings demonstrate that cystatin C may be a preferable filtration marker in these subgroups.
authors.affiliation: Department of Nephrology, Alfred Health, Melbourne, Australia. Electronic address: dovdegen@optusnet.com.au.
authors.forename: Dov A
authors.initials: DA
authors.lastname: Degen
authors.affiliation: Department of Nephrology, Alfred Health, Melbourne, Australia.
authors.forename: Jyotsna
authors.initials: J
authors.lastname: Janardan
authors.affiliation: Department of Nephrology, Alfred Health, Melbourne, Australia.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Barraclough
authors.affiliation: Alfred Pathology Service, Alfred Health, Melbourne, Australia; Central Clinical School, Monash University, Melbourne, Australia.
authors.forename: Hans G
authors.initials: HG
authors.lastname: Schneider
authors.affiliation: Department of Nuclear Medicine & PET Centre, Alfred Health, Melbourne, Australia; Department of Medicine, Monash University, Melbourne, Australia.
authors.forename: Thomas
authors.initials: T
authors.lastname: Barber
authors.affiliation: Department of Nuclear Medicine & PET Centre, Alfred Health, Melbourne, Australia.
authors.forename: Howard
authors.initials: H
authors.lastname: Barton
authors.affiliation: Central Clinical School, Monash University, Melbourne, Australia; Lung Transplant Service, Alfred Health, Melbourne, Australia.
authors.forename: Gregory
authors.initials: G
authors.lastname: Snell
authors.affiliation: Central Clinical School, Monash University, Melbourne, Australia; Lung Transplant Service, Alfred Health, Melbourne, Australia.
authors.forename: Bronwyn
authors.initials: B
authors.lastname: Levvey
authors.affiliation: Department of Nephrology, Alfred Health, Melbourne, Australia; Central Clinical School, Monash University, Melbourne, Australia.
authors.forename: Rowan G
authors.initials: RG
authors.lastname: Walker
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D003404:Creatinine / Q000097:blood*; D055316:Cystatin C / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D016040:Lung Transplantation; D008297:Male; D008875:Middle Aged; D004369:Pentetic Acid / Q000008:administration & dosage; D011237:Predictive Value of Tests; D011866:Radioisotope Renography; D019275:Radiopharmaceuticals / Q000008:administration & dosage*
chemical_list: D015415:Biomarkers; D055316:Cystatin C; D019275:Radiopharmaceuticals; D004369:Pentetic Acid; D003404:Creatinine