title: Comparison of estimated glomerular filtration rate by the chronic kidney disease epidemiology collaboration (CKD-EPI) equations with and without Cystatin C for predicting clinical outcomes in elderly women.
abstract: BACKGROUND
  Reduced estimated glomerular filtration rate (eGFR) using the cystatin-C derived equations might be a better predictor of cardiovascular disease (CVD) mortality compared with the creatinine-derived equations, but this association remains unclear in elderly individuals.
  
  
  OBJECTIVE
  The aims of this study were to compare the predictive values of the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI)-creatinine, CKD-EPI-cystatin C and CKD-EPI-creatinine-cystatin C eGFR equations for all-cause mortality and CVD events (hospitalizations±mortality).
  
  
  METHODS
  Prospective cohort study of 1165 elderly women aged>70 years. Associations between eGFR and outcomes were examined using Cox regression analysis. Test accuracy of eGFR equations for predicting outcomes was examined using Receiver Operating Characteristic (ROC) analysis and net reclassification improvement (NRI).
  
  
  RESULTS
  Risk of all-cause mortality for every incremental reduction in eGFR determined using CKD-EPI-creatinine, CKD-EPI-cystatin C and the CKD-EPI-creatinine-cystatic C equations was similar. Areas under the ROC curves of CKD-EPI-creatinine, CKD-EPI-cystatin C and CKD-EPI-creatinine-cystatin C equations for all-cause mortality were 0.604 (95%CI 0.561-0.647), 0.606 (95%CI 0.563-0.649; p = 0.963) and 0.606 (95%CI 0.563-0.649; p = 0.894) respectively. For all-cause mortality, there was no improvement in the reclassification of eGFR categories using the CKD-EPI-cystatin C (NRI -4.1%; p = 0.401) and CKD-EPI-creatinine-cystatin C (NRI -1.2%; p = 0.748) compared with CKD-EPI-creatinine equation. Similar findings were observed for CVD events.
  
  
  CONCLUSIONS
  eGFR derived from CKD-EPI cystatin C and CKD-EPI creatinine-cystatin C equations did not improve the accuracy or predictive ability for clinical events compared to CKD-EPI-creatinine equation in this cohort of elderly women.
authors.affiliation: University of Western Australia School of Medicine and Pharmacology, Sir Charles Gairdner Hospital Unit, Perth, Australia; Department of Renal Medicine, Sir Charles Gairdner Hospital, Perth, Australia.
authors.forename: Wai H
authors.initials: WH
authors.lastname: Lim
authors.affiliation: University of Western Australia School of Medicine and Pharmacology, Sir Charles Gairdner Hospital Unit, Perth, Australia; Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Perth, Australia.
authors.forename: Joshua R
authors.initials: JR
authors.lastname: Lewis
authors.affiliation: Centre for Kidney Research, Children's Hospital at Westmead, Sydney, Australia; School of Public Health, Sydney Medical School, The University of Sydney, Sydney, Australia.
authors.forename: Germaine
authors.initials: G
authors.lastname: Wong
authors.affiliation: School of Public Health, The University of New South Wales, Sydney, Australia.
authors.forename: Robin M
authors.initials: RM
authors.lastname: Turner
authors.affiliation: Department of Renal Medicine, Sir Charles Gairdner Hospital, Perth, Australia; PathWest, Sir Charles Gairdner Hospital, Perth, Australia.
authors.forename: Ee M
authors.initials: EM
authors.lastname: Lim
authors.affiliation: Department of Cardiovascular Medicine, Sir Charles Gairdner Hospital, Perth, Australia.
authors.forename: Peter L
authors.initials: PL
authors.lastname: Thompson
authors.affiliation: University of Western Australia School of Medicine and Pharmacology, Sir Charles Gairdner Hospital Unit, Perth, Australia; Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Perth, Australia.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Prince
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood*; D055316:Cystatin C / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007676:Kidney Failure, Chronic / Q000453:epidemiology / Q000503:physiopathology*; D011446:Prospective Studies; D012372:ROC Curve
chemical_list: D015415:Biomarkers; D055316:Cystatin C