title: Risk of refracture associated with compliance and persistence with bisphosphonate therapy in Taiwan.
abstract: CONCLUSIONS
  Bisphosphonates have been used for the treatment of postmenopausal osteoporosis since the early 1990s and studies show that compliant patients experience a lower fracture rate. This cohort study showed that the compliance of Taiwanese patients was poor and the refracture risk was related to compliance with bisphosphonate therapy.
  
  
  BACKGROUND
  Bisphosphonates are potent inhibitors of osteoclast activity, and reduce bone turnover by inhibiting bone resorption. According to Taiwanese reimbursement guidelines, patients with osteoporosis-related fractures are eligible for bisphosphonate treatment. This study aimed to elucidate the relationship of refracture risk with compliance/persistence with bisphosphonate therapy in Taiwan.
  
  
  METHODS
  This was a retrospective, administrative, database analysis measuring the adherence status and impact of poor adherence to bisphosphonate therapy in Taiwan. Study data derived from the National Health Insurance Research Database (NHIRD) were used to assemble a cohort of all osteoporosis patients who initiated bisphosphonate treatment between January 1, 2004, and December 31, 2005. Patients were followed until death, end of registration in NHIRD, or end of study period (December 31, 2006), whichever occurred first. Compliance was calculated as medication possession ratio (MPR; sum of days of supply of osteoporosis medications divided by follow-up duration).
  
  
  RESULTS
  The refracture rates for osteoporosis patients were 5.15 %, 7.36 %, and 8.49 % in the first, second, and third year, respectively, and were significantly lower for patients with >80 % compliance than with <80 % compliance (p < 0.05). Nearly 50 % patients were noncompliant (MPR < 80 %) at 3 months, and only around 30 % patients were adherent at 1 year. Refracture risk increased with MPR < 80 %, age, and co-morbidities like diabetes mellitus or dementia. Patients with concomitant statin medication had significantly lower refracture risk.
  
  
  CONCLUSIONS
  The compliance of Taiwanese patients with osteoporosis medication is poor, and refracture risk is related to compliance with bisphosphonate therapy.
authors.affiliation: Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital and Chang Gung University, Linkou, No. 5, Fusing St., Gueishan Township, Taoyuan County, 333, Taiwan, Republic of China. yks@adm.cgmh.org.tw
authors.forename: Y-K
authors.initials: YK
authors.lastname: Soong
authors.forename: K-S
authors.initials: KS
authors.lastname: Tsai
authors.forename: H-Y
authors.initials: HY
authors.lastname: Huang
authors.forename: R-S
authors.initials: RS
authors.lastname: Yang
authors.forename: J-F
authors.initials: JF
authors.lastname: Chen
authors.forename: P C-H
authors.initials: PC
authors.lastname: Wu
authors.forename: K-E
authors.initials: KE
authors.lastname: Huang
mesh_terms: D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D050071:Bone Density Conservation Agents / Q000627:therapeutic use*; D015897:Comorbidity; D004164:Diphosphonates / Q000627:therapeutic use*; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000188:drug therapy / Q000453:epidemiology; D058866:Osteoporotic Fractures / Q000453:epidemiology / Q000517:prevention & control*; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D055502:Secondary Prevention; D013624:Taiwan / Q000453:epidemiology; D016903:Drug Monitoring
chemical_list: D050071:Bone Density Conservation Agents; D004164:Diphosphonates