title: Effect of renal function on skeletal health in primary hyperparathyroidism.
abstract: BACKGROUND
  Current guidelines recommend parathyroidectomy in patients with primary hyperparathyroidism (PHPT) who have an estimated glomerular filtration rate (eGFR) less than 60 ml/min per 1.73 m(2). It is unclear, however, whether values below this threshold of renal impairment affect bone and mineral metabolism in PHPT.
  
  
  OBJECTIVE
  The purpose of this study was to assess the effect of renal function on skeletal health in PHPT.
  
  
  METHODS
  This is a retrospective analysis of PHPT patients with (eGFR < 60 ml/min per 1.73 m(2)) and without chronic kidney disease (CKD) from our previously described PHPT cohort recruited from 1984 to 1991.
  
  
  METHODS
  The study was conducted in a university hospital metabolic bone unit.
  
  
  METHODS
  One hundred thirty-eight women and men with PHPT were studied.
  
  
  METHODS
  We assessed bone mineral density (BMD) by dual-energy x-ray absorptiometry; quantitative histomorphometric indices from transiliac bone biopsies; and biochemical markers of mineral metabolism.
  
  
  RESULTS
  Although there was no difference in serum or urinary calcium or PTH level, calcitriol levels were lower and phosphate levels higher in patients with CKD. BMD adjusted for weight did not differ at any site between groups. Histomorphometric analysis (n = 30 of 138) revealed a 45% greater eroded surface in those with CKD (P = 0.02). Eroded surface negatively correlated with eGFR (r = -0.46, P = 0.02) and phosphate (r = -0.48, P = 0.02) and positively correlated with serum calcium level (r = 0.51, P = 0.009) but not with PTH, alkaline phosphatase, vitamin D metabolites, or urinary calcium excretion.
  
  
  CONCLUSIONS
  Although cardinal biochemical indices (such as calcium and PTH) and BMD do not differ in PHPT patients with an eGFR below 60 ml/min per 1.73 m(2), these patients have higher phosphate and histomorphometric evidence of altered bone remodeling compared with those without CKD.
authors.affiliation: Columbia University College of Physicians and Surgeons, Department of Medicine, New York, New York 10032, USA. mad2037@columbia.edu
authors.forename: Marcella D
authors.initials: MD
authors.lastname: Walker
authors.forename: David W
authors.initials: DW
authors.lastname: Dempster
authors.forename: Donald J
authors.initials: DJ
authors.lastname: McMahon
authors.forename: Julia
authors.initials: J
authors.lastname: Udesky
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Shane
authors.forename: John P
authors.initials: JP
authors.lastname: Bilezikian
authors.forename: Shonni J
authors.initials: SJ
authors.lastname: Silverberg
mesh_terms: D000328:Adult; D000368:Aged; D015519:Bone Density / Q000502:physiology*; D001842:Bone and Bones / Q000503:physiopathology*; D005260:Female; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000150:complications / Q000503:physiopathology*; D007668:Kidney / Q000503:physiopathology*; D007676:Kidney Failure, Chronic / Q000150:complications / Q000503:physiopathology*; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies