节点文献
我国医疗费用制度性非合理增长系统动力学模型研究
Study on Modeling of Institutional Unreasonable Increase of Medical Expense in China
【作者】 孔辉;
【作者基本信息】 复旦大学 , 社会医学与卫生事业管理, 2010, 硕士
【摘要】 一、研究背景和意义自改革开放以来,我国医疗卫生事业得到快速发展,与此同时也带来了医疗费用的增长。从医疗费用增长的推动因素来看,可以把医疗费用增长分为自然增长和制度性增长两个部分。自然增长是指经济发展、人口老龄化、疾病结构变化、医学技术发展等因素带来的医疗费用增长。制度性增长是指因为法律、政策等国家或地方制度性因素导致的医疗费用增长。这部分医疗费用一部分使得百姓生活受益,另一部分却是“浪费”了的资源。这些制度涉及到药品加成、医院管制、物价调整、医保补偿等多个方面,相互之间存在着拮抗、协同、因果等错综复杂的关系,并且通过数十年的磨合,已经形成了稳定的架构,最终促成了医疗费用制度性非合理增长。如果能够调整这些制度,将有助于缓解医疗费用快速增长的问题,同时又不至于损害到人民群众既有的医疗服务权益。对于我国医疗费用非合理增长的问题,国内多位学者从不同角度做过研究。大多学者认为:由于政府财政补助不足,医院只能在现有政策空间下开展业务创收。因为物价部门对于医疗服务常规项目的限制,对药品、高新项目检查等的放开,医院逐步走上“诱导服务”的道路,带来医疗费用的快速增长。在当前不完善的医疗保障制度下,百姓承受了越来越重的医疗费用负担。胡善联等学者提出了在医疗费用支付方式、医院收费驱动机制、市场竞争等方面控制医疗费用。国内已有的研究成果,为本次研究提供了坚实的基础。我们也看到,医疗服务系统是一个繁杂的社会系统。系统动力学理论和方法在解决复杂系统问题上,就目前可供选择的理论和方法学而言,系统动力学是最适合的。二、研究内容、方法和研究结果本研究以“系统动力学”作为指导性研究方法。严格遵循系统动力学的研究思路:界定问题、确定问题相关子系统、确定子系统间及内部的定性关系、建立系统动力学规范模型、检验模型等一系列规范步骤来展开医疗费用制度性非合理增长问题的研究。其中,界定问题过程在综述及引言中完成。以下为剩余步骤的研究过程及结果:(一)明确了医疗费用制度性非合理增长问题涉及的子系统1、资料来源和研究方法(1)文献检索在1990-2010年《中华医院管理杂志》、《中国卫生经济》、《中国医院管理》《中国卫生事业管理》、《卫生经济研究》、《中国初级卫生保健》、《中国农村卫生事业管理》、《中国卫生资源》等专业期刊中,以“医药卫生”为检索范围,检索标题中含有“医疗费用+增长”的文献,共计64篇;检索标题中含有“药品加成”的文献,共计29篇;检索标题中含有“医疗保障制度”而不含有“农村合作医疗”的文献,共计730篇;另外还以“医改”、“公立医院改革”、“商业医疗保险”、“医疗需求”等关键词检索多篇相关文献。通过阅读文献,归纳引起我国医疗费用增长的因素有哪些,其中哪些为合理增长因素,哪些为不合理增长因素,不合理增长的因素中哪些可以通过政策予以管制等等。明确了这些影响因素后,再探究这些因素所在子系统,或者是那个系统主体引起了这些因素的变动等等。另外,课题组还阅读了多篇专著:《城市生活垃圾管理系统动力学模型研究——以北京市为例》(蔡林著)、《环境模拟——环境系统的系统动力学模型导论》([美]Andrew Ford著,唐海萍,史培军译)等等。通过阅读这些专著,课题组了解了系统动力学的基础知识,尤其是对专著里具体实践过程中系统动力学建模过程的学习,掌握了利用系统动力学建模的步骤,常用软件(Vensim软件),等等。(2)专家小组讨论课题研究全程召开专家咨询会议共计五次,课题组内部组织每个星期的小组讨论。通过接触市卫生局医政管理处、卫生发展研究中心、合作医疗办公室,以及区县卫生局财务科、信息科等等的卫生行政公务人员,还有高校中卫生政策研究方向的专家、学者等,笔者学习、总结了关于我国医疗费用、医疗卫生体制改革等方面的大量知识。这对于本次研究中探寻医疗费用增长过程相关子系统,帮助颇大。(3)卫生系统宏观模型卫生系统宏观模型,是把握医疗卫生服务运作规律的理论模型。该模型边界非常清晰,将医疗卫生服务相关的子系统分析得十分透彻。本次研究将医疗费用作为该模型中“系统结果”的指标之一,通过探寻其前承因果关系,帮助我们以“顺藤摸瓜”的方式来寻找医疗费用制度性非合理增长问题涉及到的子系统。2、研究结果课题组首先通过文献归纳分析、专家小组讨论的方法,探寻医疗费用制度性非合理增长问题所涉及的子系统;然后从卫生系统宏观模型中然后进一步验证、确定上述子系统。最终明确下来的子系统集合包括:社会子系统、医院子系统、政府财政子系统、物价子系统、医保子系统以及百姓子系统。(二)建立了医疗费用制度性非合理增长的系统动力学模型1、建立医疗费用制度性非合理增长的系统结构框图模型(1)资料来源和研究方法本部分主要的研究方法为系统动力学中的系统结构框图。系统结构框图就是用方框或者圆圈简明地代表系统的主要子块(或者子系统)并描述它们之间的物质流、信息流的交链关系。简单地说,即是将模型涉及到的子系统,用简单的线、框,粗略地勾勒出它们之间的关系。(2)研究结果根据Andrew Ford在《环境模拟——环境系统的系统动力学模型导论》中给出的建议:“模型的建立是一个反复调试的过程。最好的方法是建立一个尽可能简单的,能够理解的参照式模型。在简单模型不足以体现现实情况时,将引起简单模型改变的变量纳入,从而转向一个更复杂的模型。最糟糕的事情莫过于一开始就试图建立‘完美模型’。”本部分首先从理想状态下医疗费用增长的简单模型的构建开始,逐步纳入制度性指标以完善模型,最终建立尽可能全面表现现实情况的医疗费用制度性非合理增长的系统结构框图模型,如图2。以医疗费用产生的子系统——医院为主线展开。医院盈余为医院总收入和医院总成本的差额。医院总成本是由三方面组成:医院公用支出、医院人力支出、医院固定资产支出。医院总收入即为显性医疗服务资金,是由三方共同偿付:医保、财政、病人自费。在理想状态下,政府财政包揽医疗费用,此时财政、医保性质相同,可以说是全民医保制度,病人无需承担自费费用。但实际中,全民医保制度并不存在,在不完善的医保制度下,必然有部分人群因医疗费用负担而医疗服务需求压抑。这部分压抑了的医疗服务需求就使得一定经济条件下的潜在医疗服务资金仅一定比例地显现出来,形成显性医疗服务资金。被压缩了的显性医疗服务资金直接带来了医院总收入的减少,医院出现亏损。与此同时,物价部门又坚守着医疗保健服务低价格的政策,压低了潜在医疗服务资金,在一定的资金显性比例下,医院收入进一步降低,医院更加亏损。医院需要利用医院盈余保障医院的发展,因此医院利用其自身垄断性等行业特性,在制度运行的空间内,走上“诱导服务”的道路,以药品、检查项目为载体,获取额外补偿。由于收益率的存在,医院实际上是通过提高医院总成本来“做大”显性医疗服务资金,从而获取医院盈余。膨胀的显性医疗服务资金,在政府财政、医保基金相对稳定的情况下,最终着落点在自费人群,带来自费病人医疗费用负担加重。在愈来愈重的费用负担下,自费病人逐步要求政府改变筹资政策,例如:要求扩大医保覆盖面、提高医保补偿比例,或者建立全民医疗保障制度等;政府在补偿、支付方面压力过大,则通过各类医院管制政策控制医院的成本支出;医院若是在政府管制下导致盈余过低,在自身发展方面受到限制,则有两个途径可走:一是要求物价部门调整医疗服务价格水平,使得医疗费用直接得到扩大;二是利用现有的医院管制政策在某些允许的方面,创造业务收入,或者要求政府在医院的管制政策上有所放松,使得医院可盈余空间加大。上述三方面即为图中病人、政府、医院的决策反馈过程。2、建立医疗费用制度性非合理增长的流图模型(1)资料来源和研究方法本部分主要的研究方法为系统动力学中的因果与相互关系图、原因树结构图和流图、牛眼图。1)因果与相互关系图我们可以简单地将因果与相互关系图可理解为系统结构框图的“丰满”过程,即:将系统结构框图中,两个系统间的粗略作用关系细致化;将系统结构框图中,概念性的子系统间,运用具体指标来链接起来。对于医疗费用的研究来说,其包含的反馈过程中有诸多连续的、类似流体流动与积累的过程。因果与相互关系图只能描述反馈结构的基本方面,一个循环或者反馈过程。本研究中要体现医疗费用增长过程中的一系列作用机制,绝非一个简单的、一步完成的过程。因此,我们在因果与相互关系图的基础上建立了相应的流图。2)原因树结构图和流图流图,是通过确定流位变量、流率变量以及辅助变量、增补变量的基础上,根据变量之间的因果关系、反馈关系,首先建立各变量的原因树结构图,然后根据各变量的原因树结构图,用相应的线条接起来,即形成模型的流图。3)牛眼图牛眼图,又被称作边界图,是一种极其简明的方法,能够显示模型的重点和需要的输入,同时也是一种便捷的方法,可以表明需要的输入与内生变量之间相对平衡的。牛眼图的表示方法是:用两个相嵌套的圆环将平面分为三部分,小圆环内部为内生变量集合,大小圆环之间为外生变量集合,大圆环以外为排除在外的变量集合。牛眼图的一个通用规则是:在牛眼图的中心找出至少三到四个关键变量,如果在牛眼图的中心漏了重要变量,这个模型也就无法为系统动态行为提供有价值的见解。(2)研究结果本部分在上一部分建立的医疗费用非合理增长的系统结构框图模型基础上,建立了医疗费用非合理增长的流图模型,如图。注:图中虚线框框出的部分为在理想状态下,纳入医保政策、物价政策、医院诱导服务等在流图中的表现。(三)定量模拟论证了医疗费用制度性非合理增长模型1、资料来源和研究方法(1)数据资料的来源收集1991-2007年《中国卫生统计年鉴》、《中国统计年鉴》、《卫生事业决算资料》,汇总了包括社会大环境指标、物价指数、政府财政、医院业务指标、人民生活指标等数据。(2)数据分析的方法一般来讲,系统动力学模型的建立、模拟过程有其专用的软件,大多数研究者运用Vensim软件进行研究。由于研究时间所限,课题组对于Vensim软件的公式编辑、定量模拟功能尚处于探索阶段。所以,本研究的定量模拟过程选用了Excel 2003软件。利用Excel的数据联动功能,以及它的描述性统计分析方法等,初步完成对定性模型的定量模拟。另外,对于模型的合理性论证,本研究采用了“面积拟合法”的方法。该方法由白求恩医科大学地方病研究所得董玉恒教授提出。为符合传统拟合优度检验的习惯,即:R2值越接近1,表明拟合优度越好;所以,在面积拟合度检验中利用如下公式来表示曲线拟合优度:面积拟合度=1-(拟合曲线与实际曲线间面积/实际曲线与均数直线间面积)(3)定量模拟的思路本研究中对当前医疗费用的模拟思路是:先模拟在理想状态下,医院的发展、百姓医疗费用与社会经济齐同增长,即:医院总收入、医院总支出的相关指标均随着GDP的增长而自然增加。建立各个指标在社会经济、社会总人口自然增长下形成的增量,即合理值。其次,模拟物价政策的严控、政府财政补助的相对不足、医院人力成本的膨胀等过程。在这些政策、制度的限定下,医院的总收入和总成本必然存在缺口;此时各个指标有其暂时的一个“模拟值”。接下来模拟医院“诱导服务”的过程。将医院为填补盈余缺口而“空转”出来的医疗费用、成本支出,加到“诱导服务”之前的“模拟值”上,即得出最终百姓医疗费用、医院各类支出等指标的模拟值。2、研究结果定量模拟出来的医疗费用与实际医疗费用的拟合情况如下图所示。依次调整定量模型中的各参数值,使得面积拟合度的值尽量趋近于1。经检验,当各相关参数如表1时,模拟医疗费用与实际医疗费用的曲线面积拟合度为0.9403,拟合效果最好。也证明了本研究中所建立的医疗费用制度性非合理增长模型的合理性。
【Abstract】 1. Research Background and SignificanceSince the reformation and opening, Chinese healthcare system has developed with a high-speed, which, at the meanwhile, brings the medical expense’s increasing. According the pushing factors of medical expense’s increasing, we divided the medical expense into two parts: the naturally increasing part and the institutionally increasing part. The former part means that the medical expense increases along with the development of economy, population’s aging, changing of disease structure and development of medical technology. The other part means the medical expense increases because of the national and local policies. Part of the medical expense brought benefit to people’s life, however, part of it was wasted. These institutional policies involved drug plus policy, hospital management, price regulation, medical insurance and the like. The relationships among these policies involved antagonist, cooperation, cause and effect and other complicated relationships. What’s more, after several decades, these relationships have run-in and hade the stable restructure, which brought the institutional unreasonable increase of medical expense. If these policies could be adjusted, the problem described above would be relieved and, at the same time, people’s benefit would not be harmed.The unreasonable increase of medical Expense is a great problem, on which many policy researchers have been studying on different aspects. Most of them concluded that: because of the insufficiency of government financial input, the hospitals have to make money by themselves in the policy environment. However, the National Development and Reform Commission limits the price of medical labor service on a low level. The hospitals have to selling drugs and providing technological examinations by medical inducement service, which brings the unreasonable increase medical Expense. Under the incomplete medical insurance system, people’s medical financial burden becomes heavier and heavier. Professor Hu Shanlian of Fudan University proposed that it should take measures on medical expense paying mode, driving mechanism of hospital charging, market competition and so on to control medical expense.The former research was the sound foundation for this study. We realized that healthcare system is a complicated social system. On solving this kind of complicated system problems, system dynamics is the most suitable.2. Material, method and resultsThis study had the "system dynamics" as its guiding research method. This study restricted its research thought to the system dynamics:defining problems, defining systems, defining the quanlitative relationships among systems, establishing system dynamics model and testing the model, among which, the step of defining problems had been done in the parts of summary and introduction. The left steps are as following:(1) Confirmed the subsystems related to the problem of institutional unreasonable increase of medical expense1) Data resource and research methods●the macro model of healthcare system The macro model of healthcare system (Chart 1) is the theory model explaining the operating rules of healthcare system. This model has a clear boundary and it analyzes the subsystems clearly. As one of the "system results", the medical expense was used in this study to seek the other subsystems involved in the problem of institutional unreasonable increase of medical expense.●Documents retrievalIn《Chinese hospital management magazine》,《Chinese healthcare economy》,《Chinese hospital management》,《healthcare economy research》,《Chinese primary healthcare》,《Chinese rural healthcare management》,《Chinese healthcare resource》and the like, in the area of healthcare, we retrieved a great many of documents by the topics of drug plus policy, medical insurance, rural cooperation medical insurance, system dynamics, healthcare reform, public hospital reform and business medical insurance and curve fitting and so on. By reading those documents, we concluded the factors resulting the increase of medical expense and among which which were the reasonable factors and which were the unreasonable ones and with those unreasonable ones how to deal by policies. After seeking out those factors, we went on to find out the subsystems where those factors stayed.In addition, we red several monographs:《System dynamics model study on the management system of city rubbish-taking the case of Beijing》(written by Cailin),《Introduction of system dynamics model of environmental system-environment simulation》(written by Andrew Ford, translated by Tang haiping and Shi peijun) and so on. By reading those books, we learned the basic knowledge of system dynamics, especially the practical modeling process. We also learned the software of Vensim.●Experts group discussionWe had organized five experts consulting conferences and several weekly group discussion meetings. By learning from professors from health bureau, healthcare development and research center, NCMS office and dept. of information, we concluded a lot, which helped us a lot in establishing the system dynamics model.2) Research resultsFirst, we found out the subsystems by the macro model of healthcare system. Then, we testified the results by the document analyzing and experts group discussion. Finally, we concluded the set of subsystems including hospital subsystem, government financial subsystem, pricing subsystem, medical insurance subsystem and patients subsystem.(2) Established the system dynamics model of institutional unreasonable increase of medical expense1) Established the system structure chart of institutional unreasonable increase of medical expense●Data resource and research methodsThe main method of this part is the system structure chart of the system dynamics. System structure chart is using a circle or a box to explain the system’s main blocks (or subsystems) and describe the material flow between them. Simply put, this method is to explain the relationships among the model subsystems by simple lines.●Research resultsAndrew Ford had given the readers a suggestion in his monograph: the model establishment is a repeating and debugging process. The best method is to establish a simple model first and then, if the simple model could not present the realism, the variable changing the model should be brought into the model. This process will lead to a completed and complicated model. The best thing is trying to establish a perfect model at the first. According to this suggestion, we established a simple model of the ideal status of the increase of medical expense at first, and then, we brought the political variables into the model gradually. Finally, we established the completed model of institutional unreasonable increase of medical expense (Chart 2).We start the explanation from the subsystem of hospital. Hospital revenues are the margin between the total cost of the hospital and the total income. The total cost of the hospital is composed of three components:public hospital expenditure, hospital labor expenses, hospital expenses of fixed assets. Hospital total income is the dominant medical services funds, which is paid by: medical insurance, finance, patient at their own expense. Ideally, the government finance undertake the whole health care costs, at this case, medical insurance nature has the same character with government finance, we can call it universal medical insurance system. Patients do not need to bear the cost at their own expense. But in fact, universal medical insurance system does not exist, in the imperfect medical insurance system, there must be some people’s medical needs depressed for medical expenses. This part of the suppressed demand for medical services made cuts the potential funding of medical services. The compressed fund of medical services directly reduces the hospital’s the total income and hospital becomes losses. At the same time, price departments of the health care services adhere to a policy of low prices, lowering the potential funding of medical services again, the hospital becomes even more losses. Hospitals need to use the surplus to protect the hospital’s development of the hospital, so the hospitals use their own characteristics of monopoly industries, under the space of the policies, going onto a road of "induction service" to obtain additional compensation. As the existence of the yield, the hospital is actually improving the hospital’s incomes through increasing its cost. Expansion of the dominant health care funds, in the condition of the stable government finance and the medical insurance fund, make the final impact point on the patients without medical insurance. In the increasingly heavy cost burden, the self-paying patient gradually urges the Government to change the funding policies, such as:requirements on expanding health insurance coverage, increasing the proportion of health insurance compensation, establishing universal health insurance system. Government, on the condition of compensation payments pressure becoming heavier, has two ways: one is to urge the price dept. to adjust the medical service price; the other is to use of existing control policies to make a business income, or to ask the government to relax the controlling policy in the hospital.2) Established the flow chart of institutional unreasonable increase of medical expense●Data resource and research methodsThe main methods of this part are the cause and effect diagram, the tree structure diagram and flow chart, bull’s-eye map.■The cause and effect diagramWe can simply understand the cause and effect diagram as the "fullness" process ot the system structure chart: specifying the relationship in system structure chart by using specific indicators to link up the variables.The process of medical expenses research contains a lot of feedbacks, similar to the fluid flow The cause and effect diagram can only describe the basic aspects of feedback, a loop or a feedback process. In this study, we need to reflect the growth of medical expense in the process of a series of mechanisms, not a simple one step process. Therefore, we established the flow diagram on the base of the cause and effect diagram.■The tree structure diagram and flow chartBy defining the current position variables, flow rate variables, auxiliary variables and added variables, according to the causal relationship and feedback relations among variables, we firstly established the reasons for each variable tree structure diagram, and then the reasons for the variable tree structure diagram, and then connected those diagrams by lines and finally established the flow chart.■Bull’s-eye mapBull’s-eye map, also being called the boundary map, is an extremely simple way to display the model’s variables. It can indicate the need for the input variables and the relative balance between endogenous variables. The way of expressing Bull’s-eye map is:using two nested rings to divide the plane into three parts, the endogenous variables are in the small ring, the exogenous variables are between the big and the small ring, other excluded variables are outside the big ring. Bull’s-eye map has a general rule:at the center of the bull’s-eye map, there at least three or four key variables, if in the center of the bull’s-eye chart there omits an important variable, there will not be a complete system model.●Research resultsThis section established the flow chart on the base of the system structure chart in the last part. Note:The dotted line frames in the chart explain the processes of adding the parts of medical insurance policy, price policy, hospital inducement service into the ideal model.(the chart is omitted)(3) Quantitatively testifying the model of institutional unreasonable increase of medical expense1) Data resource and research methods■The materials resourceThe main quantitative resource of this study is as follows:《China Statistical Yearbook》《China Medical Statistical Yearbook》、《Healthcare final accounts information》(1991-2007). We collected the indexes of social environment, price index, government finance, hospital operational index and so on.■The data analyzing methodsIn general, the software of Vensim is the professional one for system dynamics model. Considering the limited time, we chose the Excel 2003 software to complete the process of quantitatively testifying. The Excel 2003 has the data linking function and its methods of descriptive statistical analysis can support the process of quantitative simulation.In addition, in the process of demonstrating of the rationality of the model, we used the "area of fitting" method. The approach was advanced by Professor Dong Yuheng from Norman Bethune Medical University, endemic studies institution. In line with the traditional habit of goodness of fit test, that is:R2 value is closer to 1, indicating better goodness of fit, we used the following formula to represent the curves of goodness of fit面积拟合度=1-(拟合曲线与实际曲线间面积/实际曲线与均数直线间面积)■The idea of quantitatively simulationThe idea of quantitatively simulation is: Firstly, we simulate in the ideal condition, hospital developing, medical expenses increasing at the same pace with the social economy, that is:the variables related to the hospital total income and expenditure have the same increasing pace with the growth of GDP. Second, we establish the growth of various indicators under the socio-economic and the total population, that is a reasonable value. Then, we simulate price policy, the relative lack of government financial assistance, expansion of hospital procedures such as labor costs. Under the limits of these policies, the hospital’s total revenue and total costs exist gaps. At this time there are the temp "simulated value" for various indicators. The next step is to simulate the hospital’s "inducing service" process. Adding the medical expenses, costs produced by the hospital aming to fill gaps to the former "simulated value", we can have the final value of medical expenses, hospital expenses and other indicators. 2) Research resultsThe chart of the medical expense simulated and the real medical expense is as following. Adjust gradually the quantitatively simulating parameter values to make the value of the area fitting as far as possible being close to 1. Upon demonstrating, when all relevant parameters in Table 1, the simulation of the actual medical expenses and simulated medical expenses are close and the value of area fitting is 0.9403. This study also proved that the reasonable model of institutional unreasonable increase of medical expense. (the charts are omitted)