title: A population-based 2-year follow-up study on the relationship between bisphosphonates and the risk of stroke.
abstract: This study aimed to explore the effect of bisphosphonate treatment on stroke using a large population cohort study. We found that the patients who received bisphosphonate therapy were less likely to suffer a stroke than comparison patients (hazard ratio (HR) = 0.79; 95% confidence interval (CI) = 0.66-0.99; p = 0.005) during a 2-year follow-up period.
  
  
  BACKGROUND
  Animal models have suggested that bisphosphonates have a beneficial effect on the cardiovascular system. However, data on this topic in human subjects are still lacking. This study aimed to explore the protective effect of bisphosphonate treatment on stroke using a large population cohort study.
  
  
  METHODS
  We identified 2,148 patients who received bisphosphonate therapy for osteoporotic fractures. We randomly extracted 6,444 subjects with vertebral or hip fractures as a comparison group matched with the study group on age, sex, and year of index date. Each patient was individually tracked for 2 years to identify those who suffered a stroke. Stratified Cox proportional hazards regressions were performed to assess the effect of bisphosphonate treatment on the risk of stroke.
  
  
  RESULTS
  We found that 184 (8.6%) patients who received bisphosphonate therapy and 696 (10.8%) comparison patients suffered a stroke during the follow-up period. After adjusting for demographic variables and medical co-morbidities, stratified Cox proportional hazards regressions stratified by propensity score revealed that patients who received bisphosphonate therapy were less likely to suffer a stroke than comparison patients (HR = 0.79; 95% CI = 0.66-0.99). The adjusted HR for subarachnoid/intra-cerebral hemorrhage for patients who received bisphosphonate therapy was only 0.53 times (95% CI = 0.33-0.92) that of comparison patients, and the hazard of having an ischemic stroke during the 2-year follow-up period was 0.81 times that of comparison patients (95% CI = 0.65-0.96).
  
  
  CONCLUSIONS
  Patients who received bisphosphonate therapy were associated with a lower risk of stroke during a 2-year follow-up period.
authors.affiliation: Department of Physical Medicine and Rehabilitation, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: J-H
authors.initials: JH
authors.lastname: Kang
authors.forename: J J
authors.initials: JJ
authors.lastname: Keller
authors.forename: H-C
authors.initials: HC
authors.lastname: Lin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D050071:Bone Density Conservation Agents / Q000627:therapeutic use*; D004164:Diphosphonates / Q000627:therapeutic use*; D004341:Drug Evaluation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000188:drug therapy* / Q000453:epidemiology; D058866:Osteoporotic Fractures / Q000453:epidemiology / Q000517:prevention & control; D018570:Risk Assessment / Q000379:methods; D020521:Stroke / Q000453:epidemiology / Q000517:prevention & control*; D013624:Taiwan / Q000453:epidemiology
chemical_list: D050071:Bone Density Conservation Agents; D004164:Diphosphonates