title: Does eGFR improve the diagnostic capability of S-Creatinine concentration results? A retrospective population based study.
abstract: The use of MDRD-eGFR to diagnose Chronic Kidney Disease (CKD) is based on the assumption that the algorithm will minimize the influence of age, gender and ethnicity that is observed in S-Creatinine concentration and thus allow a single cut-off at which further diagnostic and therapeutic actions should be considered. This hypothesis is tested in a retrospective analysis of outpatients (N=93,404) and hospitalised (N=35,572) patients in UK and Sweden, respectively. An algorithm based on the same model as the MDRD-eGFR algorithm was derived from simultaneously measured S-Creatinine concentrations and Iohexol GFR in a subset of 565 patients. The combined uncertainty of using this algorithm was estimated to about 15 % which is about three times that of the S-Creatinine concentration results. The diagnostic performance of S-Creatinine concentration was evaluated using the Iohexol clearance as the reference procedure. It was shown that the diagnostic capacity of MDRD-eGFR, as it stands, has no added value compared to S-Creatinine. The gender and age differences of the S-Creatinine concentrations in the dataset persist after applying the MDRD-eGFR algorithm. Thus, a general use of the MDRD-eGFR does not seem justified. Furthermore the claim that the eGFR is adjusted for body area is misleading; the algorithm does not include any body size marker. It is thus a dangerous marker for guiding drug administration.
authors.affiliation: Department of Clinical Chemistry, Karolinska University Hospital, SE 17176, Stockholm, Sweden. anders.kallner@ki.se
authors.forename: Anders
authors.initials: A
authors.lastname: Kallner
authors.forename: Peter A
authors.initials: PA
authors.lastname: Ayling
authors.forename: Zahra
authors.initials: Z
authors.lastname: Khatami
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D015331:Cohort Studies; D003287:Contrast Media / Q000493:pharmacokinetics; D003404:Creatinine / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006801:Humans; D007297:Inpatients; D007472:Iohexol / Q000493:pharmacokinetics; D007676:Kidney Failure, Chronic / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D010045:Outpatients; D012372:ROC Curve; D012016:Reference Values; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D017678:Sex Distribution; D013548:Sweden / Q000453:epidemiology; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D003287:Contrast Media; D007472:Iohexol; D003404:Creatinine