title: Impact of vitamin D replacement in patients with normocalcaemic and hypercalcaemic primary hyperparathyroidism and coexisting vitamin D deficiency.
abstract: BACKGROUND
  Vitamin D deficiency is increasingly recognized in patients with primary hyperparathyroidism but some clinicians are reluctant to replace vitamin D due to concerns with aggravating hypercalcaemia. We investigated the impact of vitamin D repletion in asymptomatic patients with normocalcaemic and hypercalcaemic primary hyperparathyroidism.
  
  
  METHODS
  This is a retrospective analysis of 111 patients with elevated parathyroid hormone concentrations (>6.4 pmol/L) referred to our endocrine clinic between January and December 2012; we identified 39 patients with primary hyperparathyroidism and vitamin D deficiency, i.e. 25 hydroxy vitamin D <20 µg/L. Patients were categorized into normocalcaemic (n = 23) and hypercalcaemic (n = 16) groups and the impact on biochemical parameters was recorded after at least six months treatment with either 1600 or 3200 units daily of cholecalciferol.
  
  
  RESULTS
  Both normocalcaemic and hypercalcaemic groups showed a rise in 25 hydroxy vitamin D concentrations after replacement (p <0.0001). Parathyroid hormone concentrations fell in the normocalcaemic group (p = 0.08) but individually, five patients showed a rise (8-38% of baseline). In the hypercalcaemic group, parathyroid hormone remained static but the adjusted calcium concentration fell significantly (p = 0.006) except in two patients who showed mild rises (3 and 6%, respectively). There was no deterioration in renal function or calcium-related adverse events in any of the groups.
  
  
  CONCLUSIONS
  Our study supports the safety of vitamin D replacement in patients with mild asymptomatic primary hyperparathyroidism and coexistent vitamin D deficiency. Repletion does not aggravate hypercalcaemia and may limit disease progression. Patients with normocalcaemic primary hyperparathyroidism need further characterization from longitudinal studies.
authors.affiliation: Department of Endocrinology, Prince Charles Hospital, Cwm Taf University Health Board, Merthyr Tydfil, UK gautam.das@wales.nhs.uk.
authors.forename: Gautam
authors.initials: G
authors.lastname: Das
authors.affiliation: Department of Endocrinology, University Hospital of Wales, Cardiff and Vale University Health Board, Cardiff, UK.
authors.forename: Vinay
authors.initials: V
authors.lastname: Eligar
authors.affiliation: Department of Endocrinology, University Hospital of Wales, Cardiff and Vale University Health Board, Cardiff, UK.
authors.forename: Jyothish
authors.initials: J
authors.lastname: Govindan
authors.affiliation: Department of Endocrinology, University Hospital of Wales, Cardiff and Vale University Health Board, Cardiff, UK.
authors.forename: L N R
authors.initials: LN
authors.lastname: Bondugulapati
authors.affiliation: Department of Endocrinology, Prince Charles Hospital, Cwm Taf University Health Board, Merthyr Tydfil, UK.
authors.forename: Onyebuchi
authors.initials: O
authors.lastname: Okosieme
authors.affiliation: Department of Endocrinology, University Hospital of Wales, Cardiff and Vale University Health Board, Cardiff, UK.
authors.forename: Steve
authors.initials: S
authors.lastname: Davies
mesh_terms: D000368:Aged; D002118:Calcium / Q000097:blood*; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000150:complications*; D049950:Hyperparathyroidism, Primary / Q000150:complications*; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D012189:Retrospective Studies; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood / Q000627:therapeutic use; D014808:Vitamin D Deficiency / Q000150:complications / Q000188:drug therapy*
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D002118:Calcium
keywords: Primary hyperparathyroidism; hypercalcaemic; normocalcaemic; parathormone; vitamin D