Abstract: This paper focuses on how zero markup reform changes the allocation of medical expenditure among different diseasesIn the first place, this paper uses four waves of the China Health and Retirement Longitudinal Study (CHARLS) data to conduct a differenceindifference analysis to identify the redistribution effect of medical expenditure allocation among different diseasesThe results show that, after the reform, a tenpercent rise in regional drug sale reliance will make the medical expenditure of an average patient increase by 513%However, a onestandard deviation increase in the patient's severity will make the increase of his total expenditure decrease by 298%Secondly, this paper discusses and tests empirically the possible causes of this phenomenon under the framework of twodimensional heterogeneity in income and severityThe paper shows that the zeromarkup reform increases the relative price of treatments that are more suitable for severe conditions and therefore encourages physicians to overuse themHowever, the usage of these treatments is quite different among patients with different income levelsHighincome patients with milder conditions are more likely to use them, but lowincome patients with more severe conditions are relatively less likely to use themThis micro mechanism leads to the misallocation of medical resources among different conditions

Key words: income inequality, zero markup reform, relative price change, severity of diseases, medical expenditure

摘要： 本文主要研究药品零加成改革引起的医疗支出在病情间的再分配效应。首先，本文利用中国健康与养老追踪调查进行双重差分分析，讨论改革对医疗支出在病情间分配的影响。回归结果显示，地区平均药占比每增加10个百分点，病情严重程度等于均值的患者的总治疗费用将显著上升513%。在此基础上，病情严重程度每增加1个标准差，患者的总治疗费用将少增加298%。进一步，本文在患者收入、病情二维异质性的框架下讨论了这种现象可能的成因并从实证上进行验证。分析表明，改革提高了对重症更有益的诊疗手段的相对价格，改变了医生在诊疗方案上的选择。这种改变会因患者的支付能力不同而有差异，相比收入低且病情较重的患者，医生更多地对收入高且病情较轻的患者使用了对重症更有益的诊疗手段。这种微观选择引起了医疗资源在病情间的扭曲配置和医疗支出向轻病的倾斜。

关键词: 收入不平等, 药品零加成, 相对价格变化, 病情, 医疗支出