title: A comparison of calcium acetate/magnesium carbonate and sevelamer-hydrochloride effects on fibroblast growth factor-23 and bone markers: post hoc evaluation from a controlled, randomized study.
abstract: BACKGROUND
  Different phosphate binders exert differing effects on bone mineral metabolism and levels of regulating hormones. The objective of this post hoc evaluation of the CALcium acetate MAGnesium carbonate (CALMAG) study was to compare the effects of calcium acetate/magnesium carbonate (CaMg) and a calcium-free phosphate binder, sevelamer-hydrochloride (HCl), on serum levels of fibroblast growth factor-23 (FGF-23) and markers of bone turnover.
  
  
  METHODS
  This secondary analysis of the controlled, randomized CALMAG study, comparing the effect of CaMg and sevelamer-HCl on serum phosphorus (P), aimed to investigate the parameters described above. The analysis included 204 patients who completed the initial study per protocol (CaMg, n = 105; sevelamer-HCl, n = 99).
  
  
  RESULTS
  The study showed that serum levels of FGF-23 were significantly reduced with CaMg and sevelamer-HCl, with no difference between groups at Week 25 [analysis of covariance (ANCOVA); log-intact FGF-23 (iFGF-23), P = 0.1573]. FGF-23 levels strongly correlated with serum P levels at all time points in both groups. The bone turnover parameters alkaline phosphatase (AP), bone AP (BAP), procollagen type 1 amino-terminal propeptide 1 (P1NP), osteoprotegerin (OPG), beta-crosslaps (β-CTX) and tartrate-resistant acid phosphatase 5b (TRAP 5b) increased significantly in the sevelamer-HCl group; they remained almost unchanged in the CaMg group, after the initial phase of P lowering (ANCOVA, P < 0.0001 for all except OPG, P = 0.1718).
  
  
  CONCLUSIONS
  CaMg and sevelamer-HCl comparably lower serum levels of iFGF-23. Changes in bone parameters were dependent on characteristics of the phosphate binder; in contrast with sevelamer-HCl, CaMg had no influence on bone turnover markers.
authors.affiliation: Clinic of Nephrology, C. I. Parhon University Hospital, Gr T. Popa; University of Medicine and Pharmacy, IASI, Romania.
authors.forename: Adrian
authors.initials: A
authors.lastname: Covic
authors.forename: Jutta
authors.initials: J
authors.lastname: Passlick-Deetjen
authors.forename: Miroslaw
authors.initials: M
authors.lastname: Kroczak
authors.forename: Beatrix
authors.initials: B
authors.lastname: Büschges-Seraphin
authors.forename: Adrian
authors.initials: A
authors.lastname: Ghenu
authors.forename: Pedro
authors.initials: P
authors.lastname: Ponce
authors.forename: Barbara
authors.initials: B
authors.lastname: Marzell
authors.forename: Angel L M
authors.initials: AL
authors.lastname: de Francisco
mesh_terms: D000085:Acetates / Q000494:pharmacology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000469:Alkaline Phosphatase / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D001842:Bone and Bones / Q000378:metabolism*; D017610:Calcium Compounds / Q000494:pharmacology; D002614:Chelating Agents / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000378:metabolism*; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D006801:Humans; D054559:Hyperphosphatemia / Q000188:drug therapy* / Q000378:metabolism; D007676:Kidney Failure, Chronic / Q000188:drug therapy / Q000378:metabolism*; D007677:Kidney Function Tests; D008274:Magnesium / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000378:metabolism; D011073:Polyamines / Q000494:pharmacology*; D011379:Prognosis; D006435:Renal Dialysis; D012307:Risk Factors; D000069603:Sevelamer; D055815:Young Adult
chemical_list: D000085:Acetates; D015415:Biomarkers; D017610:Calcium Compounds; D002614:Chelating Agents; C000717427:FGF23 protein, human; D010281:Parathyroid Hormone; D011073:Polyamines; C005479:magnesium carbonate; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23; D000069603:Sevelamer; D000469:Alkaline Phosphatase; D008274:Magnesium; C120662:calcium acetate
keywords: bone markers; calcium acetate; fibroblast growth factor-23; haemodialysis; magnesium carbonate; phosphate binder