本文研究目的為探討支付制度的變革對醫療供給者醫療行為的影響，我們以醫師醫治之冠狀動脈繞道手術(Coronary Artery Bypass Graft，以下稱CABG)和經皮冠狀動脈擴張術(Percutaneous Transluminal Coronary Angioplasty，以下稱PTCA)病患的醫療利用及醫療結果為醫師行為改變指標。健保局為節省醫療費用支出，於1999年7月1日將CABG與PTCA的醫療給付由論量計酬改為論病計酬，此支付制度的改變，對執行較多CABG和PTCA手術量或較高比例之醫師的影響，比執行較少或低手術比例之醫師為大，我們利用差異中的差異(Difference-in-difference)分析方法，來比較在制度變化前後，高手術比例與低手術比例醫師之病人，其醫療利用和醫療結果的差異，並用此差異來凸顯醫療供給者對制度變化的反應。本研究資料來源為的全民健保資料庫，以1999年7月1日制度改變前後2.5年(即1997年至2001年)，接受CABG和PTCA之病人為觀察樣本。我們分別以CABG和PTCA手術比例25%、30%、35%來界定高手術比例醫師(實驗組)和低手術比例醫師(控制組)，並利用差異中的差異方法，搭配一般線性機率模型和一般複迴歸模型來進行實證分析。我們的研究結果顯示在醫療利用的部分，高手術比例之醫師相較於低手術比例之醫師，皆有較大的誘因去降低治療病患的醫療費用，其中PTCA之醫療費用降低的結果較明顯；而在醫療結果的部分，我們的研究顯示，高手術比例之醫師相較於低手術比例之醫師，其治療病患皆有較高的出院後30天內死亡率和再住院率，且達到統計上的顯著性，此隱含支付制度由論量計酬改變為論病計酬會對病患的醫療結果有負面的影響。因此，本研究證實支付制度的改革的確有會影響醫師的行為，致使病患醫療利用降低，醫療結果變差。The goal of this paper is to investigate the effect of a change of payment system on physicians’ behavior, which is indicated by the level of medical utilization and treatment outcome of the coronary artery heart disease patients who take the Percutaneous Transluminal Coronary Angioplasty(PTCA) and Coronary Artery Bypass Graft(CABG) surgery. For the reason of cost saving, the Bureau of National Health changed the payment to PTCA and CABG from fee-for–services to case payment at July 1, 1999. This is expected to enhance the financial risk to cardiologists, leading them to change behaviors when caring patients, especially for those who conduct a large share of PTCA and CABG surgery volume. By employing the 1997-2001 National Health Insurance database, we compare the before/after difference of the medical utilization and treatment outcome of patients who are cared by the cardiologists with different share of PTCA and CABG surgery volume via difference-in-difference technique. Our empirical results show that, after the implementation of case payment, the level of medical care utilization is lower for the PTCA patients and 30-day mortality rate is higher for CABG patients cared by high-shared cardiologists. This implies that the switch of payment system from fee-for-services to case payment will reduce the patients’ medical care utilization. However, the reform of payment system also brings an adverse effect on patients’ treatment outcome.
