OBJECTIVES: Upon the coverage restriction proposed by Taiwan National Health Insurance (NHI), the dual antiplatelet therapy (DAT) with clopidogrel and aspirin could be reimbursed up to 9 months for some specific indications since 2004. The longer duration of DAT was allowed for the cases with drug eluting stent (DES) since late 2006. Although evidence showed its risks outweighed the benefits comparing to use aspirin alone, it is a lack of study examining the population use of DAT in Taiwan. A secondary data analysis was performed to examine the use patterns of DAT, specifically among the older adults in Taiwan. METHODS: A population-based longitudinal assessment was conducted using the 2003-2007 NHI databases. Those beneficiaries in 60 years old of age and greater during the study period were evaluated. All relevant data, including visits toward physician clinics, outpatient departments, use of medications, and pertinent covered cost in the datasets of ambulatory care were retrieved and analyzed. Descriptive analysis was performed to describe the utilization and duration of DAT. RESULTS: Of one million beneficiaries being evaluated, 1511 older patients (age= 70.8± 8.0 years old) were prescribed DAT. A sharply increasing prescription of DAT occurred in 2007. 85.6% were prescribed with approval indications (i.e., ischemic heart diseases) for aspirin or clopidogrel alone. 31% possessed with at least one atherothrombotic risk factors (DM, dyslipidemia), which might attribute to DAT. The duration of DAT was up to 13 months. About 10% had DAT for more than 9 months. CONCLUSIONS: A sharply increasing utilization of DAT among Taiwanese older adults occurred in 2007. The change of reimbursement policy for DES in Taiwan may be the major contributing factor. However, further studies are needed to explore other contributing factors of DAT and its effectiveness and safety outcomes.