title: Incidence and risk of venous thromboembolism among Taiwan osteoporotic fracture population under osteoporosis pharmacological treatments.
abstract: BACKGROUND
  There was no clear evidence for the association between oral bisphosphonates or raloxifene and venous thromboembolism (VTE). There might also be ethnic differences in VTE risk.
  
  
  OBJECTIVE
  The purpose of this study was to compare the incidence and risk of VTEs for different classes of osteoporosis drugs in the Taiwanese osteoporotic fracture population.
  
  
  METHODS
  This was a retrospective cohort study from 2003 to 2007, with up to 6 years follow-up.
  
  
  METHODS
  Enrollees were participants in Taiwan National Health Insurance.
  
  
  METHODS
  PATIENTS older than 50 years who had vertebral or hip fractures and were new to osteoporosis therapy were recruited.
  
  
  METHODS
  PATIENTS were classified into the alendronate, calcitonin, or raloxifene group according to exposure after follow-up.
  
  
  METHODS
  The primary outcome of our study was all incident VTEs, including deep vein thrombosis and pulmonary embolism. Cox proportional hazard models were used to compare the relative VTE risk among alendronate, raloxifene, and calcitonin groups under an on-treatment scenario.
  
  
  RESULTS
  There were 25 443, 9642, and 31 900 patients in the alendronate, raloxifene, and calcitonin groups, and the mean age was 74.5 years (SD, 9.6). The incidence of VTE in the alendronate, raloxifene, and calcitonin groups was 11.2, 8.5, and 18.8 per 10 000 person-years. Results from Cox analyses showed that alendronate or raloxifene recipients did not have a higher risk for VTE than calcitonin recipients (adjusted hazard ratio for alendronate, 0.84; 95% confidence interval, 0.47-1.51; adjusted hazard ratio for raloxifene, 0.64; 95% confidence interval, 0.33-1.28).
  
  
  CONCLUSIONS
  This retrospective analysis found that the incidence of VTE in Taiwanese patients with osteoporosis was low, and the risk of VTE was similar across alendronate, raloxifene, and calcitonin recipients in patients with osteoporotic fractures who were new to osteoporosis therapy.
authors.affiliation: Institute of Clinical Pharmacy and Pharmaceutical Sciences (T.-C.L., Y.-H.K.Y.), Department of Orthopedics (C.-Y.Y.), and Department of Internal Medicine (C.-H.L.), College of Medicine, Department of Orthopedics (C.-Y.Y.), and Health Outcome Research Center (T.-C.L., Y.-H.K.Y., S.-J.L.), National Cheng Kung University, Tainan 701, Taiwan; and Department of Pharmacy Administration (S.-J.L.), University of Illinois at Chicago, Chicago, Illinois 60612.
authors.forename: Tzu-Chieh
authors.initials: TC
authors.lastname: Lin
authors.forename: Cheng-Han
authors.initials: CH
authors.lastname: Lee
authors.forename: Chyun-Yu
authors.initials: CY
authors.lastname: Yang
authors.forename: Yea-Huei Kao
authors.initials: YH
authors.lastname: Yang
authors.forename: Swu-Jane
authors.initials: SJ
authors.lastname: Lin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019386:Alendronate / Q000009:adverse effects / Q000627:therapeutic use; D050071:Bone Density Conservation Agents / Q000009:adverse effects / Q000627:therapeutic use; D002116:Calcitonin / Q000009:adverse effects / Q000627:therapeutic use; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000188:drug therapy* / Q000453:epidemiology; D058866:Osteoporotic Fractures / Q000453:epidemiology*; D020849:Raloxifene Hydrochloride / Q000009:adverse effects / Q000627:therapeutic use; D012189:Retrospective Studies; D012306:Risk; D013624:Taiwan / Q000453:epidemiology; D054556:Venous Thromboembolism / Q000453:epidemiology*
chemical_list: D050071:Bone Density Conservation Agents; D020849:Raloxifene Hydrochloride; D002116:Calcitonin; D019386:Alendronate