title: Parathyroid hormone changes following denosumab treatment in postmenopausal osteoporosis.
abstract: OBJECTIVE
  Denosumab is a new potent antiresorptive treatment of osteoporosis that can potentially induce a compensatory increase in parathyroid hormone (PTH) levels. We aimed to evaluate the alteration of PTH 1 and 6 months after denosumab's administration with different regimens of calcium and vitamin D (Ca/D) supplementation.
  
  
  METHODS
  Prospective, multicenter, study in a relatively small, heterogeneous sample of postmenopausal women followed for 6 months.
  
  
  METHODS
  Forty seven postmenopausal women followed in 2 outpatient clinics, requiring onset or continuation of osteoporosis treatment. We administered 1 g calcium carbonate and 800 IU cholecalciferol daily for 6 months (Group A) or the double dose for the first month followed by the 1 g/800 IU Ca/D regimen for the next 5 months (Group B).
  
  
  METHODS
  Parathyroid hormone (PTH) alterations between and within groups, and their associations with serum Ca and bone markers.
  
  
  RESULTS
  Parathyroid hormone (PTH) levels were significantly higher at month 1 and 6 only in Group A; Ca levels were significantly decreased at month 1 and returned to baseline values at month 6 within the same Group. The mean per cent change between month 1 and baseline for PTH [Δ(PTH1-0 )] was significantly higher in Group A than B (63·5% ± 28·2% vs -3·0% ± 4·7%, P = 0·029). Δ(PTH1-0 ) was correlated with the reciprocal Δ-changes of Ca (rs  = -0·610; P = 0·002) and collagen type I C-terminal telopeptide (rs  = -0·697; P = 0·003) only in Group A.
  
  
  CONCLUSIONS
  An increase in PTH should be expected, at least following the first administration of denosumab in common clinical practice. The effect of this compensatory onsequence in bone metabolism warrants further investigation.
authors: Department of Endocrinology and Diabetes, 251 Hellenic Air Force & VA General Hospital, 3 Kanellopoulou St, Goudi, Athens. makras@internet.gr
authors: Polyzois
authors: P
authors: Makras
authors: Stergios A
authors: SA
authors: Polyzos
authors: Athanasios
authors: A
authors: Papatheodorou
authors: Panagiotis
authors: P
authors: Kokkoris
authors: Daniel
authors: D
authors: Chatzifotiadis
authors: Athanasios D
authors: AD
authors: Anastasilakis
mesh_terms: D000368:Aged; D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use*; D015519:Bone Density / Q000187:drug effects; D002118:Calcium / Q000097:blood; D002119:Calcium Carbonate / Q000627:therapeutic use; D002762:Cholecalciferol / Q000627:therapeutic use; D000069448:Denosumab; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000097:blood* / Q000188:drug therapy*; D010281:Parathyroid Hormone / Q000097:blood*; D011446:Prospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D014815:Vitamins / Q000627:therapeutic use
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D010281:Parathyroid Hormone; D014815:Vitamins; D002762:Cholecalciferol; D000069448:Denosumab; D002119:Calcium Carbonate; D002118:Calcium