Fibroblast growth factor-23 and parathyroid hormone are associated with post-transplant bone mineral density loss.
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.
Kanaan
Nada
N
Department of Nephrology, Cliniques Universitaires Saint-Luc, 10, Av Hippocrate, 1200 Brussels, Belgium. nada.kanaan@uclouvain.be
Claes
Kathleen
K
Devogelaer
Jean-Pierre
JP
Vanderschueren
Dirk
D
Depresseux
Genevieve
G
Goffin
Eric
E
Evenepoel
Pieter
P
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
D015415:Biomarkers; C000717427:FGF23 protein, human; C470125:PTH protein, human; D010281:Parathyroid Hormone; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23