title: Iohexol clearance is superior to creatinine-based renal function estimating equations in detecting short-term renal function decline in chronic heart failure.
abstract: OBJECTIVE
  To compare the performance of iohexol plasma clearance and creatinine-based renal function estimating equations in monitoring longitudinal renal function changes in chronic heart failure (CHF) patients, and to assess the effects of body composition on the equation performance.
  
  
  METHODS
  Iohexol plasma clearance was measured in 43 CHF patients at baseline and after at least 6 months. Simultaneously, renal function was estimated with five creatinine-based equations (four- and six-variable Modification of Diet in Renal Disease, Cockcroft-Gault, Cockcroft-Gault adjusted for lean body mass, Chronic Kidney Disease Epidemiology Collaboration equation) and body composition was assessed using bioimpedance and dual-energy x-ray absorptiometry.
  
  
  RESULTS
  Over a median follow-up of 7.5 months (range 6-17 months), iohexol clearance significantly declined (52.8 vs 44.4 mL/[min ×1.73 m2], P=0.001). This decline was significantly higher in patients receiving mineralocorticoid receptor antagonists at baseline (mean decline -22% of baseline value vs -3%, P=0.037). Mean serum creatinine concentration did not change significantly during follow-up and no creatinine-based renal function estimating equation was able to detect the significant longitudinal decline of renal function determined by iohexol clearance. After accounting for body composition, the accuracy of the equations improved, but not their ability to detect renal function decline.
  
  
  CONCLUSIONS
  Renal function measured with iohexol plasma clearance showed relevant decline in CHF patients, particularly in those treated with mineralocorticoid receptor antagonists. None of the equations for renal function estimation was able to detect these changes. ClinicalTrials.gov registration number: NCT01829880.
authors.forename: Katja
authors.initials: K
authors.lastname: Cvan Trobec
authors.forename: Mojca
authors.initials: M
authors.lastname: Kerec Kos
authors.forename: Stephan
authors.initials: S
authors.lastname: von Haehling
authors.forename: Stefan D
authors.initials: SD
authors.lastname: Anker
authors.forename: Iain C
authors.initials: IC
authors.lastname: Macdougall
authors.forename: Piotr
authors.initials: P
authors.lastname: Ponikowski
authors.affiliation: Mitja Lainscak, Associate Professor of Internal Medicine, General Hospital Celje, SI-Celje, mitja.lainscak@guest.arnes.si.
authors.forename: Mitja
authors.initials: M
authors.lastname: Lainscak
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease; D003404:Creatinine / Q000097:blood; D005260:Female; D005919:Glomerular Filtration Rate; D006333:Heart Failure / Q000150:complications*; D006801:Humans; D007472:Iohexol / Q000494:pharmacology*; D007674:Kidney Diseases / Q000175:diagnosis* / Q000209:etiology*; D007677:Kidney Function Tests / Q000379:methods*; D008297:Male
chemical_list: D007472:Iohexol; D003404:Creatinine