title: Impacts of drug reimbursement reductions on utilization and expenditures of oral antidiabetic medications in Taiwan: an interrupted time series study.
abstract: OBJECTIVE
  To control increasing pharmaceutical expenditures, Taiwan's National Health Insurance has implemented a series of drug reimbursement price reductions since 2000. This study examined changes in use and expenditures of oral antidiabetic medications following the price regulation in November 2006.
  
  
  METHODS
  We obtained claims data between January 2006 and August 2007 from Taiwan's National Health Insurance Research Database. We categorized oral antidiabetic products as affected by the reimbursement reduction ("targeted") or not ("non-targeted"), by level of relative price reduction, and by manufacturer type (international vs. local manufacturers). We used an interrupted time series design and segmented regression models to estimate changes in monthly per capita prescribing rate, volume, and insurance reimbursement expenditures following the policy.
  
  
  RESULTS
  The majority (129/178; 72.5%) of oral antidiabetic products were targeted by this round of price reductions. There was a relative reduction of 9.5% [95%CI: -12.68, -6.32] in total expenditures at ten months post-policy compared to expected rates. For targeted products, there were 2.04% [95%CI: -4.15, 0.07] and 13.26% [95%CI: -16.64, -9.87] relative reductions in prescribing rate and expenditures, respectively, at ten months post-policy. Non-targeted products increased significantly (22% [95%CI: 10.49, 33.51] and 22.85% [95%CI: 11.69, 34.01] relative increases in prescribing rate and expenditures respectively). Larger reimbursement cuts led to greater reductions in prescribing rate, volume, and insurance reimbursement expenditures of targeted products. Prescribing rates of both targeted and non-targeted products by international manufacturers declined after the policy while rates of prescribing non-targeted products by local manufacturers increased.
  
  
  CONCLUSIONS
  While total government expenditures for oral antidiabetic medications were contained by the policy, our results indicate that prescribing shifted at the margin from targeted to non-targeted products and from international to local products. Further research is warranted to understand how changes in medication use due to price regulation policies affect medication adherence and patient health outcomes.
authors: Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, MA, USA; National Center for Pharmaceutical Regulatory Science, College of Medicine, National Cheng Kung University, Taiwan. Electronic address: jasonhsuharvard@gmail.com.
authors: Jason C
authors: JC
authors: Hsu
authors: Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, MA, USA.
authors: Christine Y
authors: CY
authors: Lu
authors: Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, MA, USA.
authors: Anita K
authors: AK
authors: Wagner
authors: Graduate Institute of Oncology, College of Medicine, National Taiwan University, Taiwan; Department of Medical Research, National Taiwan University Hospital, Taiwan.
authors: K Arnold
authors: KA
authors: Chan
authors: Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taiwan.
authors: Mei-Shu
authors: MS
authors: Lai
authors: Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, MA, USA.
authors: Dennis
authors: D
authors: Ross-Degnan
mesh_terms: D016527:Drug Costs / Q000706:statistics & numerical data*; D006801:Humans; D007004:Hypoglycemic Agents / Q000191:economics / Q000627:therapeutic use*; D065186:Interrupted Time Series Analysis; D009313:National Health Programs / Q000458:organization & administration / Q000706:statistics & numerical data; D012051:Reimbursement Mechanisms / Q000191:economics / Q000458:organization & administration / Q000706:statistics & numerical data; D013624:Taiwan / Q000453:epidemiology
chemical_list: D007004:Hypoglycemic Agents
keywords: Drug reimbursement reduction; Interrupted time series; Oral hypoglycemic medications