title: Reduced bone density in patients on long-term warfarin.
abstract: OBJECTIVE
  Vitamin K is an essential factor for carboxylation of bone matrix protein. Low vitamin K may be associated with reduced bone mineral density (BMD). The issue of whether long-term sodium warfarin therapy as oral anticoagulant that antagonizes vitamin K, results in decreased bone density, is controversial. Our purpose in this study was to assess the effects of warfarin on BMD.
  
  
  METHODS
  We performed a case control study survey of bone density in 70 patients with rheumatic valvular heart disease 'mechanical valve replacement' on long-term warfarin compared with 103 randomly selected matched controls.
  
  
  RESULTS
  There was a marked reduction in BMD (g/cm(2)) and T-score of lumbar spine between patients and controls (P = 0.048, 0.005). Duration of warfarin use was the only risk factor of significant importance respectively on spinal T-score (P < 0.03).
  
  
  CONCLUSIONS
  Screening of patients on long-term warfarin for reduced bone density should be considered. We strongly suggest the prophylactic use of calcium-vitamin D supplements for these patients.
authors.affiliation: Department of Rheumatology, Mashhad University of Medical Sciences, Mashhad, Iran. rezaieyazdi-z@mums.ac.ir
authors.forename: Zahra
authors.initials: Z
authors.lastname: Rezaieyazdi
authors.forename: Homa
authors.initials: H
authors.lastname: Falsoleiman
authors.forename: Mohammad
authors.initials: M
authors.lastname: Khajehdaluee
authors.forename: Masoud
authors.initials: M
authors.lastname: Saghafi
authors.forename: Elham
authors.initials: E
authors.lastname: Mokhtari-Amirmajdi
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D000925:Anticoagulants / Q000009:adverse effects*; D015519:Bone Density / Q000187:drug effects* / Q000502:physiology; D016022:Case-Control Studies; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging; D006306:Health Surveys; D006350:Heart Valve Prosthesis; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000139:chemically induced* / Q000000981:diagnostic imaging; D012214:Rheumatic Heart Disease / Q000188:drug therapy* / Q000601:surgery; D014812:Vitamin K / Q000037:antagonists & inhibitors / Q000378:metabolism; D014859:Warfarin / Q000009:adverse effects*
chemical_list: D000925:Anticoagulants; D014812:Vitamin K; D014859:Warfarin