Fibroblast growth factor 23 in hemodialysis patients: effects of phosphate binder, calcitriol and calcium concentration in the dialysate.
BACKGROUND
Fibroblast growth factor 23 (FGF23) concentrations increase early in chronic kidney disease (CKD), and the influence of current CKD-mineral and bone disorder (MBD) therapies on serum FGF23 levels is still under investigation.


METHODS
In this post-hoc analysis of a randomized clinical trial, phosphate binders and calcitriol were washed out of 72 hemodialysis patients who were then submitted to bone biopsy, coronary tomography and biochemical measures, including FGF23. They were randomized to receive sevelamer or calcium acetate for 1 year and the prescription of calcitriol and the calcium concentration in the dialysate were adjusted according to serum calcium, phosphate and PTH and bone biopsy diagnosis.


RESULTS
At baseline, bone biopsy showed that 58.3% had low-turnover bone disease, whereas 38.9% had high-turnover bone disease, with no significant differences between them with regard to FGF23. Median baseline FGF23 serum levels were elevated and correlated positively with serum phosphate. After 1 year, serum FGF23 decreased significantly. Repeated measures ANOVA analysis showed that the use of a 3.5-mEq/l calcium concentration in the dialysate, as well as the administration of calcitriol and a calcium-based phosphate binder were associated with higher final serum FGF23 levels.


CONCLUSIONS
Taken together, our results confirm that the current CKD-MBD therapies have an effect on serum levels of FGF23. Since FGF23 is emerging as a potential treatment target, our findings should be taken into account in the decision on how to manage CKD-MBD therapy.
Cancela
Ana L E
AL
Universidade de São Paulo, São Paulo, Brazil.
Oliveira
Rodrigo B
RB
Graciolli
Fabiana G
FG
dos Reis
Luciene M
LM
Barreto
Fellype
F
Barreto
Daniela V
DV
Cuppari
Lilian
L
Jorgetti
Vanda
V
Carvalho
Aluizio B
AB
Canziani
Maria Eugênia
ME
Moysés
Rosa M A
RM
D000085:Acetates / Q000008:administration & dosage / Q000494:pharmacology; D000328:Adult; D000704:Analysis of Variance; D001706:Biopsy; D050071:Bone Density Conservation Agents / Q000008:administration & dosage / Q000494:pharmacology; D001847:Bone Diseases / Q000150:complications / Q000188:drug therapy* / Q000473:pathology; D001842:Bone and Bones / Q000473:pathology*; D002114:Calcinosis / Q000000981:diagnostic imaging*; D002117:Calcitriol / Q000008:administration & dosage / Q000494:pharmacology; D002118:Calcium / Q000008:administration & dosage / Q000494:pharmacology; D017610:Calcium Compounds / Q000008:administration & dosage / Q000494:pharmacology; D002614:Chelating Agents / Q000008:administration & dosage / Q000494:pharmacology; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D015314:Dialysis Solutions / Q000737:chemistry / Q000627:therapeutic use*; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood* / Q000187:drug effects*; D005500:Follow-Up Studies; D006801:Humans; D007676:Kidney Failure, Chronic / Q000150:complications / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010710:Phosphates / Q000097:blood; D011073:Polyamines / Q000008:administration & dosage / Q000494:pharmacology; D000069603:Sevelamer; D014057:Tomography, X-Ray Computed
D000085:Acetates; D050071:Bone Density Conservation Agents; D017610:Calcium Compounds; D002614:Chelating Agents; D015314:Dialysis Solutions; C000717427:FGF23 protein, human; D010710:Phosphates; D011073:Polyamines; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23; D000069603:Sevelamer; D002117:Calcitriol; D002118:Calcium; C120662:calcium acetate