title: Estimation of kidney function in cancer patients.
abstract: BACKGROUND
  The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula has not been validated in patients with cancer. The present investigation was undertaken in order to study how well estimated glomerular filtration rate (eGFR) using the new CKD-EPI equation correlates with measured GFR (mGFR) by (51)chrome ethylene diamine tetraacetic acid ((51)Cr-EDTA) clearance in a group of patients with cancer not known as having cancer.
  
  
  METHODS
  We investigated 185 patients with cancer who were referred for isotope measurement of GFR with (51)Cr-EDTA before initiating chemotherapy treatment. The agreement between CKD-EPI and (51)Cr-EDTA was assessed using a Bland-Altman plot. Test performance was analysed in a contingency table and bias, precision and the percentage of estimates within 30% of the mGFR (P30) were assessed.
  
  
  RESULTS
  Bland-Altman plot analysis showed a limit of agreement in the range from -25.59 to 27.92 ml/min./1.73 m(2). This formula was therefore not interchangeable with (51)Cr-EDTA, as the above differences are of clinical importance. Bias was low: 1.16 ml/min./1.73 m(2); P30 was high: 89.73%; and precision was 13.37 ml/min./1.73 m(2). As a screening test, the CKD-EPI had a high specificity of 98% (95% confidence interval (CI): 96 to 100%) and a high negative predictive value 97% (95% CI: 95 to 100%). The accuracy of the validation test was 96% (95% CI: 93 to 99%).
  
  
  CONCLUSIONS
  The CKD-EPI may be used as a screening tool for CKD in the general population, but cannot replace isotope tests when a high GFR measurement accuracy is needed.
authors.affiliation: Department of Nephrology, Division of Nephrology, Roskilde Hospital, Denmark. belenredal@hotmail.com
authors.forename: Belén
authors.initials: B
authors.lastname: Redal-Baigorri
authors.forename: Knud Heine
authors.initials: KH
authors.lastname: Stokholm
authors.forename: Knud
authors.initials: K
authors.lastname: Rasmussen
authors.forename: Nina
authors.initials: N
authors.lastname: Jeppesen
mesh_terms: D002614:Chelating Agents / Q000008:administration & dosage / Q000378:metabolism; D016001:Confidence Intervals; D003404:Creatinine / Q000378:metabolism; D004492:Edetic Acid / Q000008:administration & dosage / Q000378:metabolism; D005260:Female; D005919:Glomerular Filtration Rate; D006305:Health Status Indicators; D006801:Humans; D007668:Kidney / Q000473:pathology*; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D002614:Chelating Agents; D004492:Edetic Acid; D003404:Creatinine