title: Association between common iron store markers and hemoglobin in children with chronic kidney disease.
abstract: BACKGROUND
  Serum ferritin and transferrin saturation (TSAT) are used to assess iron status in children with chronic kidney disease (CKD), but their sensitivity in identifying those at risk of lower hemoglobin (HGB) values is unclear.
  
  
  METHODS
  We assessed the association of iron status markers (ferritin, TSAT, and serum iron) with age- and gender-related HGB percentile in mild-to-moderate CKD in 304 children in the Chronic Kidney Disease in Children (CKiD) Study. Standardized HGB percentile values were examined by KDOQI-recommended ferritin (≥ 100 ng/ml) and TSAT (≥ 20 %) thresholds. Regression tree methods were used to identify iron status markers and clinical characteristics most associated with lower HGB percentiles.
  
  
  RESULTS
  The cohort was 62 % male, 23 % African American, and 12 % Hispanic, median age 12 years, and median HGB 12.9 g/dl. 34 % had low TSAT and 93 % low ferritin as defined by KDOQI. Distribution of HGB percentile values was lower in those with ferritin ≥ 100 ng/ml, while TSAT ≥ 20 % was associated with only modest increase in HGB percentile. In regression tree analysis, lower glomerular filtration rate (GFR), serum iron <50 μg/dl and ferritin ≥ 100 ng/ml were most strongly associated with lower HGB percentile.
  
  
  CONCLUSIONS
  The level of GFR was significantly associated with HGB. Higher serum ferritin was associated with lower HGB in this cohort. Low serum iron in the context of normal/increased ferritin and low HGB may be a useful indicator of iron-restricted erythropoiesis.
authors: Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA. matkins3@jhmi.edu
authors: Meredith A
authors: MA
authors: Atkinson
authors: Christopher B
authors: CB
authors: Pierce
authors: Jeffrey J
authors: JJ
authors: Fadrowski
authors: Nadine M
authors: NM
authors: Benador
authors: Colin T
authors: CT
authors: White
authors: Martin A
authors: MA
authors: Turman
authors: Cynthia G
authors: CG
authors: Pan
authors: Alison G
authors: AG
authors: Abraham
authors: Bradley A
authors: BA
authors: Warady
authors: Susan L
authors: SL
authors: Furth
mesh_terms: D015415:Biomarkers / Q000032:analysis / Q000097:blood; D002648:Child; D005260:Female; D005293:Ferritins / Q000097:blood*; D005919:Glomerular Filtration Rate; D006454:Hemoglobins / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D007501:Iron / Q000097:blood*; D008297:Male; D051436:Renal Insufficiency, Chronic / Q000097:blood*; D014168:Transferrin / Q000032:analysis / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D006454:Hemoglobins; D014168:Transferrin; D005293:Ferritins; D007501:Iron