title: Calcium metabolism in the early posttransplantation period.
abstract: OBJECTIVE
  Information on the time course of serum calcium levels after renal transplantation is scanty, especially in the early posttransplantation period. Both the abrupt cessation of calcium-containing phosphorus binders and vitamin D (analogs) at the time of surgery and the recovery of renal function may be hypothesized to affect serum calcium levels in this period.
  
  
  METHODS
  In this prospective observational study, biointact parathyroid hormone, calcidiol, calcitriol, calcium, and phosphorus levels were monitored in 201 renal transplant recipients at the time of transplantation and 3 mo thereafter. In addition, the serum calcium nadir and peak in each individual patient within this time frame were identified and the urinary fractional calcium excretion was determined at month 3.
  
  
  RESULTS
  Serum calcium levels followed a biphasic pattern with a significant decline during the first postoperative week, followed by a significant increase. High pretransplantation parathyroid hormone levels protect against hypocalcemia within the first postoperative week but put patients at risk for hypercalcemia later. These complications, occurring in 41 and 14% of the patients, respectively, most probably reflect inappropriate calcium release from the skeleton, rather than inappropriate renal calcium handling.
  
  
  CONCLUSIONS
  Our data indicate that both hypo- and hypercalcemia are prevalent in the early posttransplantation period. Pretransplantation parathyroid function is an important predictor of posttransplantation calcium levels.
authors.affiliation: Department of Medicine, Division of Nephrology, University Hospital Leuven, Leuven, Belgium. pieter.evenepoel@uz.kuleuven.ac.be
authors.forename: Pieter
authors.initials: P
authors.lastname: Evenepoel
authors.forename: Barbara
authors.initials: B
authors.lastname: Van Den Bergh
authors.forename: Maarten
authors.initials: M
authors.lastname: Naesens
authors.forename: Hylke
authors.initials: H
authors.lastname: De Jonge
authors.forename: Bert
authors.initials: B
authors.lastname: Bammens
authors.forename: Kathleen
authors.initials: K
authors.lastname: Claes
authors.forename: Dirk
authors.initials: D
authors.lastname: Kuypers
authors.forename: Yves
authors.initials: Y
authors.lastname: Vanrenterghem
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D002112:Calcifediol / Q000097:blood; D002117:Calcitriol / Q000097:blood; D002118:Calcium / Q000097:blood / Q000378:metabolism* / Q000652:urine; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000097:blood / Q000209:etiology* / Q000652:urine; D006996:Hypocalcemia / Q000097:blood / Q000209:etiology* / Q000652:urine; D016030:Kidney Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D010758:Phosphorus / Q000097:blood; D011184:Postoperative Period; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D010281:Parathyroid Hormone; D010758:Phosphorus; D002117:Calcitriol; D002112:Calcifediol; D002118:Calcium