title: Zolpidem use and risk of fracture in elderly insomnia patients.
abstract: OBJECTIVE
  To evaluate the risk of fractures related with zolpidem in elderly insomnia patients.
  
  
  METHODS
  Health claims data on the entire South Korean elderly population from January 2005 to June 2006 were extracted from the Health Insurance Review and Assessment Service database. We applied a case-crossover design. Cases were defined as insomnia patients who had a fracture diagnosis. We set the hazard period of 1 day length prior to the fracture date and four control periods of the same length at 5, 10, 15, and 20 weeks prior to the fracture date. Time independent confounding factors such as age, gender, lifestyle, cognitive function level, mobility, socioeconomic status, residential environment, and comorbidity could be controlled using the case-crossover design. Time dependent confounding factors, especially co-medication of patients during the study period, were adjusted by conditional logistic regression analysis. The odds ratios and their 95% confidence intervals (CIs) were estimated for the risk of fracture related to zolpidem.
  
  
  RESULTS
  One thousand five hundred and eight cases of fracture were detected in insomnia patients during the study period. In our data, the use of zolpidem increased the risk of fracture significantly (adjusted odds ratio [aOR], 1.72; 95% CI, 1.37 to 2.16). However, the association between benzodiazepine hypnotics and the risk of fracture was not statistically significant (aOR, 1.00; 95% CI, 0.83 to 1.21). Likewise, the results were not statistically significant in stratified analysis with each benzodiazepine generic subgroup.
  
  
  CONCLUSIONS
  Zolpidem could increase the risk of fracture in elderly insomnia patients. Therefore zolpidem should be prescribed carefully and the elderly should be provided with sufficient patient education.
authors.affiliation: Department of Preventive Medicine, Seoul National University College of Medicine, Korea.
authors.forename: Dong-Yoon
authors.initials: DY
authors.lastname: Kang
authors.forename: Soyoung
authors.initials: S
authors.lastname: Park
authors.forename: Chul-Woo
authors.initials: CW
authors.lastname: Rhee
authors.forename: Ye-Jee
authors.initials: YJ
authors.lastname: Kim
authors.forename: Nam-Kyong
authors.initials: NK
authors.lastname: Choi
authors.forename: Joongyub
authors.initials: J
authors.lastname: Lee
authors.forename: Byung-Joo
authors.initials: BJ
authors.lastname: Park
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001569:Benzodiazepines / Q000009:adverse effects / Q000627:therapeutic use; D018592:Cross-Over Studies; D005260:Female; D050723:Fractures, Bone / Q000139:chemically induced / Q000453:epidemiology*; D006801:Humans; D006993:Hypnotics and Sedatives / Q000009:adverse effects / Q000627:therapeutic use; D008297:Male; D016017:Odds Ratio; D011725:Pyridines / Q000009:adverse effects* / Q000627:therapeutic use*; D056910:Republic of Korea / Q000453:epidemiology; D018570:Risk Assessment; D012307:Risk Factors; D007319:Sleep Initiation and Maintenance Disorders / Q000188:drug therapy*; D000077334:Zolpidem
chemical_list: D006993:Hypnotics and Sedatives; D011725:Pyridines; D001569:Benzodiazepines; D000077334:Zolpidem