title: Fibroblast growth factor-23 and parathyroid hormone are associated with post-transplant bone mineral density loss.
abstract: OBJECTIVE
  Among the multiple factors contributing to bone mineral density (BMD) loss after renal transplantation, hypophosphatemia is increasingly recognized to play an important role. Hypophosphatemia occurs in up to 90% of the renal transplant recipients in the early post-transplant period and is caused by renal phosphate wasting. We hypothesized that a high pretransplant level of the recently described phosphaturic hormone fibroblast growth factor 23 (FGF-23) is a risk factor for accelerated BMD loss occurring within the first post-transplant year.
  
  
  METHODS
  We performed a two-center observational retrospective cohort study in 127 incident renal transplant recipients. Serum full-length FGF-23, parathyroid hormone (PTH), and parameters of mineral metabolism were determined at the time of transplantation. BMD was assessed by osteodensitometry at the time of transplantation and 1 year later.
  
  
  RESULTS
  A moderate decrease of BMD was observed during the first post-transplant year. High FGF-23 levels were associated with BMD loss at the lumbar spine and total hip region, whereas low PTH levels were associated with BMD loss at all three regions. Cumulative doses of prednisone and post-transplant serum phosphate level were not correlated with BMD changes.
  
  
  CONCLUSIONS
  Our data indicate that patients with a high serum FGF-23 level and/or a low PTH level at the time of transplantation are at risk for increased BMD loss during the first post-transplant year.
authors.affiliation: Department of Nephrology, Cliniques Universitaires Saint-Luc, 10, Av Hippocrate, 1200 Brussels, Belgium. nada.kanaan@uclouvain.be
authors.forename: Nada
authors.initials: N
authors.lastname: Kanaan
authors.forename: Kathleen
authors.initials: K
authors.lastname: Claes
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Devogelaer
authors.forename: Dirk
authors.initials: D
authors.lastname: Vanderschueren
authors.forename: Genevieve
authors.initials: G
authors.lastname: Depresseux
authors.forename: Eric
authors.initials: E
authors.lastname: Goffin
authors.forename: Pieter
authors.initials: P
authors.lastname: Evenepoel
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D001530:Belgium; D015415:Biomarkers / Q000097:blood; D015519:Bone Density; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood*; D006621:Hip Joint / Q000000981:diagnostic imaging; D006801:Humans; D017674:Hypophosphatemia / Q000097:blood / Q000000981:diagnostic imaging / Q000209:etiology*; D015592:Immunoradiometric Assay; D016030:Kidney Transplantation / Q000009:adverse effects*; D016014:Linear Models; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; C000717427:FGF23 protein, human; C470125:PTH protein, human; D010281:Parathyroid Hormone; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23