title: The effects of mineral metabolism markers on renal transplant outcomes.
abstract: BACKGROUND
  Hyperparathyroidism is a common complication of chronic renal failure. A functioning kidney graft improves hyperparathyroidism but it can persist to some degree for years. Persistent hyperparathyroidism associated with hypercalcemia and hyperphosphatemia have been associated with poor graft and patient survivals. The purpose of the present work was to assess the association between calcium/phosphate mineral metabolism markers and graft outcomes.
  
  
  METHODS
  Among 389 renal transplantations performed in our center between January 2000 and June 2008, 331 patients had functioning grafts at 12 months, the subjects of this study. Measurements of intact parathyroid hormone (iPTH), serum calcium and phosphate, tubular phosphate reabsorption, and urinary calcium excretion were performed at 1, 3, 6, and 12 months. The mean follow-up was 84.0 ± 31.8 months.
  
  
  RESULTS
  During the follow-up period, 63 grafts (19.0%) were lost, 30 patients (9.0%) died, and 80 recipients (24.2%) presented at least one cardiovascular event. Univariate Cox proportional analysis showed high iPTH levels at 1 and 12 months after transplantation to not be associated with worse patient or graft survival or an higher risk of cardiovascular events. Serum phosphate and calcium concentrations as well as calcium-phosphate products during the first year after transplantation were not associated with graft and patient outcomes or cardiovascular events. However, serum calcium at 12 months showed an inverse association with graft survival after adjusting for other variables (hazard ratio 0.61; 95% confidence interval 0.40-0.94; P = .026).
  
  
  CONCLUSIONS
  iPTH levels and serum phosphate concentrations and calcium-phosphate products during the first year after transplantation were not associated with graft outcomes. The inverse association between adjusted calcium and graft survival should be studied further.
authors.affiliation: Department of Nephrology, Hospital Ramón y Cajal, Madrid, Spain. rmarcen.hrc@salud.madrid.org
authors.forename: R
authors.initials: R
authors.lastname: Marcén
authors.forename: S
authors.initials: S
authors.lastname: Jimenez
authors.forename: A
authors.initials: A
authors.lastname: Fernández
authors.forename: C
authors.initials: C
authors.lastname: Galeano
authors.forename: J J
authors.initials: JJ
authors.lastname: Villafruela
authors.forename: F J
authors.initials: FJ
authors.lastname: Burgos
authors.forename: C
authors.initials: C
authors.lastname: Quereda
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood / Q000652:urine; D002118:Calcium / Q000097:blood / Q000652:urine; D016009:Chi-Square Distribution; D005260:Female; D006085:Graft Survival; D006801:Humans; D006961:Hyperparathyroidism / Q000097:blood / Q000209:etiology* / Q000401:mortality; D007676:Kidney Failure, Chronic / Q000097:blood / Q000150:complications / Q000601:surgery* / Q000652:urine; D016030:Kidney Transplantation / Q000009:adverse effects / Q000401:mortality; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010281:Parathyroid Hormone / Q000097:blood; D010710:Phosphates / Q000097:blood / Q000652:urine; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; C470125:PTH protein, human; D010281:Parathyroid Hormone; D010710:Phosphates; D002118:Calcium