抗血小板藥物用於預防中風復發之成本效果分析 -以台灣為例

目前臨床上用來預防缺血性中風復發的藥物以抗血小板藥物為主。早期， aspirin是抗血小板藥物之中減少此類型中風復發的第一選擇。近年來，開始有其他的抗血小板藥物問世，包含 clopidogrel以及新的複方抗血小板藥物： aspirin加上 modified-release dipyridamole。然而這些新藥的價格都比 aspirin來得昂貴，且台灣目前尚未有相關的藥物經濟學研究，因此有進行這類藥品成本效果分析之必要。故本研究將採用台灣資料來探討使用新的抗血小板藥物是否符合成本效益。

研究方法： 藉由二年馬可夫模式，以台灣健保局觀點進行成本效果分析。研究對象為 65歲以上曾經發生過一次缺血性中風的病患。欲分析的藥物有 aspirin， clopidgorel，以及 aspirin加上 modified-release dipyridamole(簡稱 ASA+MR-DP)。以上三項藥品將進行兩兩組間比較，探討使用何者藥品比較符合成本效益。主要測量的結果變項為生活品質校正年(Quality-adjusted life-year, QALY)。

研究結果： 兩年初步分析結果顯示，使用 ASA+MR-DP病患的生活品質校正年為 1.948年，成本花費為 45,310元；而使用 aspirin病患的生活品質校正年為 1.946年，成本花費為 33,623元；兩者的邊際效益比值 (ICER)為 1,889,544元 /QALY。使用 clopidogrel病患的生活品質校正年為 1.948年，成本花費為 68,334元，與 aspirin相比之後的邊際效益比值為 9,699,399元 /QALY。進行單維敏感性分析時發現，變項為「抗血小板藥物對於預防中風復發的效果」以及「抗血小板藥物藥價」，此兩項變項的改變會造成邊際效益比值變化甚大，進而可能影響研究結論之改變。

Cost-Effectiveness Analysis of Antiplatelet Therapy in the Prevention of Recurrent Stroke in Taiwan

Antiplatelet agents can prevent recurrent stroke. Aspirin is the most widely studied one and, until recently, it was the only drug used broadly for this purpose. Now, clinical trials indicate that ticlopidine, clopidogrel, and a combination regimen, aspirin plus modified-release dipyridamole (ASA+MR-DP), are also effective for prevention of recurrent stroke. However, these new antiplatelet agents are more expensive than aspirin. In Taiwan, their cost-effectiveness ratios relative to aspirin have not been estimated.

Method： Markov model is developed to measure the clinical benefit and economic consequences of the following st

rategies to treat high-risk patients aged 65 years or older: (1) aspirin 100mg once a day; (2) aspirin 25mg plus modified-release dipyridamole 200mg (ASA+MR-DP) twice a day; and (3) clopidogrel 75mg once a day. Input data were obtained from literature review. Cost and quality-adjusted life-year (QALY) are primary outcomes measured. The time frame is two years.

Results： The use of aspirin combined with dipyridamole was slightly effective and more costly compared the use of

aspirin: direct cost per one patient is NTD 45,310, and estimated QALY for one patient is 1.948 years; in aspirin group: direct cost per one patient is NTD 33,623, and estimated QALY for one patient is 1.946 years. The Incremental cost-effectiveness ratio (ICER) between aspirin and ASA+MR-DP is NTD 1,889,544 per QALY. The comparison between aspirin and clopidogrel: The incremental cost-effectiveness ratio between aspirin and clopidogrel is NTD 9,699,399 per QALY. In sensitivity analyses, the efficacy and drug prices of antiplatelet agents are key factors to determine the ICER compared with aspirin.

Conclusion： Comparing new antiplatelet agents to aspirin, our results show that using new drugs is cost-effective, it me

ans using new drug has better outcome, but induces highly medical direct cost.