title: Serum iron markers are inadequate for guiding iron repletion in chronic kidney disease.
abstract: OBJECTIVE
  Iron (Fe) overload may complicate parenteral Fe therapy used to enhance the efficacy of erythropoietic-stimulating agents in the treatment of anemia of chronic kidney disease. However, serum Fe markers are influenced by inflammation or malignancy and may not accurately reflect the amount of body Fe.
  
  
  METHODS
  We studied the relationship between parenteral Fe therapy, conventional serum Fe markers, and liver iron concentration (LIC) measured using magnetic resonance R2 relaxometry (FerriScan) in 25 Fe-deficient predialysis chronic kidney disease patients before and 2 and 12 weeks after single high-dose intravenous Fe and in 15 chronic hemodialysis patients with elevated serum ferritin (>500 μg/L).
  
  
  RESULTS
  In predialysis patients, there was strong dose dependency between the administered Fe dose and changes in LIC at weeks 2 and 12; however, no dose dependency between Fe dose and changes in ferritin or transferrin saturation (TSAT) were observed. In hemodialysis patients, LIC correlated with the cumulative Fe dose and duration of dialysis but not with current ferritin or TSAT. The cumulative Fe dose remained a significant independent predictor of LIC in a multiple regression model. Two dialysis patients who received >6 g parenteral Fe had substantially elevated LIC >130 μmol/g, which is associated with hemochromatosis.
  
  
  CONCLUSIONS
  In Fe-deficient predialysis patients, intravenous Fe therapy is associated with increases in LIC unrelated to changes in conventional Fe markers. In hemodialysis patients, TSAT and ferritin are poor indicators of body Fe load, and some patients have LICs similar to those found in hemochromatosis.
authors.affiliation: Department of Nephrology, Fremantle Hospital, Alma Street, Perth, Western Australia 6160, Australia. paolo.ferrari@health.wa.gov.au
authors.forename: Paolo
authors.initials: P
authors.lastname: Ferrari
authors.forename: Hemant
authors.initials: H
authors.lastname: Kulkarni
authors.forename: Shyam
authors.initials: S
authors.lastname: Dheda
authors.forename: Susanne
authors.initials: S
authors.lastname: Betti
authors.forename: Colin
authors.initials: C
authors.lastname: Harrison
authors.forename: Timothy G
authors.initials: TG
authors.lastname: St Pierre
authors.forename: John K
authors.initials: JK
authors.lastname: Olynyk
mesh_terms: D000328:Adult; D000368:Aged; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D005260:Female; D005293:Ferritins / Q000097:blood*; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007501:Iron / Q000627:therapeutic use*; D000090463:Iron Deficiencies; D007674:Kidney Diseases / Q000097:blood*; D008099:Liver / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D006435:Renal Dialysis; D014168:Transferrin / Q000032:analysis*
chemical_list: D006454:Hemoglobins; D014168:Transferrin; D005293:Ferritins; D007501:Iron