title: Estimation of Glomerular Filtration Rate in Patients With Cirrhosis by Using New and Conventional Filtration Markers and Dimethylarginines.
abstract: OBJECTIVE
  Equations used to estimate glomerular filtration rate (GFR) are not accurate in patients with cirrhosis. We aimed to develop a new equation to estimate the GFR in subjects with cirrhosis and compare its performance with chronic kidney disease epidemiology collaboration (CKD-EPI) cystatin C and creatinine-cystatin C equations, which were derived in populations without cirrhosis.
  
  
  METHODS
  From 2010 through 2014, we measured GFR in 103 subjects with cirrhosis based on non-radiolabeled iothalamate plasma clearance. We measured blood levels of creatinine, cystatin C, β-trace protein, β2-microglobulin, L-arginine, and symmetric and asymmetric dimethylarginines simultaneously with GFR. Multivariate linear regression analysis was performed to develop models to estimate GFR. Overall accuracy, defined by the root mean square error (RMSE) of our newly developed model to estimate GFR, was compared with that of the CKD-EPI equations. To obtain an unbiased estimate of our new equation to estimate GFR, we used a leave-one-out cross-validation strategy.
  
  
  RESULTS
  After we considered all the candidate variables and blood markers of GFR, the most accurate equation we identified to estimate GFR included serum levels of creatinine and cystatin C, as well as patients' age, sex, and race. Overall, the accuracy of this equation (RMSE = 22.92) was superior to that of the CKD-EPI cystatin C equation (RMSE = 27.27, P = .004). Among subjects with cirrhosis and diuretic-refractory ascites, the accuracy of the equation we developed to estimate GFR (RMSE = 19.36) was greater than that of the CKD-EPI cystatin C (RMSE = 27.30, P = .003) and CKD-EPI creatinine-cystatin C equations (RMSE = 23.37, P = .004).
  
  
  CONCLUSIONS
  We developed an equation that estimates GFR in subjects with cirrhosis and diuretic-refractory ascites with greater accuracy than the CKD-EPI cystatin C equation or CKD-EPI creatinine-cystatin C equation.
authors.affiliation: Department of Medicine, Division of Gastroenterology and Hepatology, University of Maryland School of Medicine, Baltimore, Maryland. Electronic address: amindiko@medicine.umaryland.edu.
authors.forename: Ayse L
authors.initials: AL
authors.lastname: Mindikoglu
authors.affiliation: Ferris State University, College of Pharmacy, Grand Rapids, Michigan.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Dowling
authors.affiliation: Department of Epidemiology and Public Health, Division of Biostatistics and Bioinformatics, University of Maryland School of Medicine, Baltimore, Maryland.
authors.forename: Laurence S
authors.initials: LS
authors.lastname: Magder
authors.affiliation: Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Christenson
authors.affiliation: Department of Medicine, Division of Nephrology, University of Maryland School of Medicine, Baltimore, Maryland.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Weir
authors.affiliation: Department of Medicine, Division of Nephrology, University of Maryland School of Medicine, Baltimore, Maryland.
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Seliger
authors.affiliation: Department of Medicine, Division of Gastroenterology and Hepatology, University of Maryland School of Medicine, Baltimore, Maryland.
authors.forename: William R
authors.initials: WR
authors.lastname: Hutson
authors.affiliation: Department of Medicine, Howard University College of Medicine, Washington, District of Columbia.
authors.forename: Charles D
authors.initials: CD
authors.lastname: Howell
mesh_terms: D000328:Adult; D000368:Aged; D001120:Arginine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D001201:Ascites / Q000150:complications*; D003404:Creatinine / Q000493:pharmacokinetics; D055316:Cystatin C / Q000493:pharmacokinetics; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007674:Kidney Diseases / Q000175:diagnosis*; D007677:Kidney Function Tests / Q000379:methods*; D008103:Liver Cirrhosis / Q000150:complications*; D008297:Male; D008875:Middle Aged
chemical_list: D055316:Cystatin C; C487735:dimethylarginine; D001120:Arginine; D003404:Creatinine
keywords: Diagnostic; End-stage Liver Disease; Liver Transplantation; Prognostic Factor