title: Fibroblast growth factor-23 is associated with C-reactive protein, serum phosphate and bone mineral density in chronic kidney disease.
abstract: We investigated the association between fibroblast growth factor-23 (FGF-23) and (1) the biochemical parameters implicated in chronic kidney disorder (CKD)-bone and mineral disorder (CKD-MBD) and (2) bone mineral density (BMD) in patients with CKD 1-4. C-reactive protein (CRP) and serum phosphate correlated with FGF-23. A significant association was seen between FGF-23 and BMD at the hip.
  
  
  BACKGROUND
  Circulating FGF-23 is elevated in CKD, although the primary stimulus remains unclear. Moreover, it is still unknown whether increase in FGF-23 has a biological effect on bone metabolism. The aim of the study was to investigate the association of FGF-23 with (1) the biochemical parameters linked with CKD-bone and mineral disorder (CKD-MBD) and (2) bone mineral density in CKD.
  
  
  METHODS
  We studied 145 patients (74 M, 71 F) aged (mean [SD]) 53 [14] years with CKD 1-4. Serum calcium, phosphate, parathyroid hormone, FGF-23, 25 (OH) vitamin D, 1, 25 (OH)(2) vitamin D, bone turnover markers, CRP were determined. BMD was measured at the lumbar spine, femoral neck (FN), forearm, and total hip (TH). Multivariate analysis was undertaken to explore the association between (1) the biochemical variables and FGF-23 and (2) FGF-23 and BMD.
  
  
  RESULTS
  Elevations in FGF-23 occurred in CKD stage 3 compared to CKD stage 1/2, although no significant differences in serum phosphate were observed. Serum phosphate (p<0.001), CRP (p<0.001) and diabetes mellitus (p<0.05) were associated with FGF-23. BMD Z-score was significantly lower at the TH and FN in CKD 4 (p<0.05). A significant association was seen between BMI, FGF-23, bone specific alkaline phosphatase and BMD at the TH (p<0.05).
  
  
  CONCLUSIONS
  The data suggest that FGF-23 may be associated with parameters implicated in the complications of CKD. Longitudinal studies are required for further clinical evaluation.
authors.affiliation: Department of Chemical Pathology, 5th Floor, North Wing, St Thomas' Hospital, Lambeth Palace Road, London, SE1 7EH, UK.
authors.forename: P
authors.initials: P
authors.lastname: Manghat
authors.forename: W D
authors.initials: WD
authors.lastname: Fraser
authors.forename: A S
authors.initials: AS
authors.lastname: Wierzbicki
authors.forename: I
authors.initials: I
authors.lastname: Fogelman
authors.forename: D J
authors.initials: DJ
authors.lastname: Goldsmith
authors.forename: G
authors.initials: G
authors.lastname: Hampson
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D015519:Bone Density / Q000502:physiology*; D002097:C-Reactive Protein / Q000032:analysis*; D012080:Chronic Kidney Disease-Mineral and Bone Disorder / Q000097:blood* / Q000503:physiopathology; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood*; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D010710:Phosphates / Q000097:blood*; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000503:physiopathology; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; C000717427:FGF23 protein, human; D010710:Phosphates; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23; D002097:C-Reactive Protein