title: Fibroblast growth factor 23 is associated with proteinuria and smoking in chronic kidney disease: an analysis of the MASTERPLAN cohort.
abstract: BACKGROUND
  Fibroblast growth factor 23 (FGF23) has emerged as a risk factor for cardiovascular disease and mortality throughout all stages of chronic kidney disease (CKD), independent from established risk factors and markers of mineral homeostasis. The relation of FGF23 with other renal and non-renal cardiovascular risk factors is not well established.
  
  
  METHODS
  Using stored samples, plasma FGF23 was determined in 604 patients with moderate to severe kidney disease that participated in the MASTERPLAN study (ISRCTN73187232). The association of FGF23 with demographic and clinical parameters was evaluated using multivariable regression models.
  
  
  RESULTS
  Mean age in the study population was 60 years and eGFR was 37 (± 14) ml/min/1.73 m(2). Median proteinuria was 0.3 g/24 hours [IQR 0.1-0.9]. FGF23 level was 116 RU/ml [67-203] median and IQR. Using multivariable analysis the natural logarithm of FGF23 was positively associated with history of cardiovascular disease (B = 0.224 RU/ml; p = 0.002), presence of diabetes (B = 0.159 RU/ml; p = 0.035), smoking (B = 0.313 RU/ml; p < 0.001), phosphate level (B = 0.297 per mmol/l; p = 0.0024), lnPTH (B = 0.244 per pmol/l; p < 0.001) and proteinuria (B = 0.064 per gram/24 hrs; p = 0.002) and negatively associated with eGFR (B = -0.022 per ml/min/1.73 m(2); p < 0.001).
  
  
  CONCLUSIONS
  Our study demonstrates that in patients with CKD, FGF23 is related to proteinuria and smoking. We confirm the relation between FGF23 and other cardiovascular risk factors.
authors.affiliation: Department of Nephrology and ICaR-VU, VU university medical centre, Amsterdam, The Netherlands. m.vervloet@vumc.nl
authors.forename: Marc G
authors.initials: MG
authors.lastname: Vervloet
authors.forename: Arjan D
authors.initials: AD
authors.lastname: van Zuilen
authors.forename: Annemieke C
authors.initials: AC
authors.lastname: Heijboer
authors.forename: Piet M
authors.initials: PM
authors.lastname: ter Wee
authors.forename: Michiel L
authors.initials: ML
authors.lastname: Bots
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Blankestijn
authors.forename: Jack F M
authors.initials: JF
authors.lastname: Wetzels
mesh_terms: D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D015995:Prevalence; D011507:Proteinuria / Q000097:blood* / Q000453:epidemiology*; D018570:Risk Assessment; D012307:Risk Factors; D012907:Smoking / Q000097:blood* / Q000453:epidemiology*
chemical_list: D015415:Biomarkers; C000717427:FGF23 protein, human; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23