《健康经济学》课件Chapter14.ppt

1、IntroHealth technology assessment(HTA)is comprised of two parts:Cost effectiveness analysis(the science of comparing the costs and benefits of different medical treatments)Cost-benefit analysis(the process of choosing an optimal treatment by creating a tradeoff between money and health)HTA may sound

2、 dry and technical but it generates enormous controversy because it involves placing an explicit value on human life.Ch 14|Health technology assessmentCOST EFFECTIVENESS ANALYSISCost effectiveness analysisDefinition:the process of measuring the costs and health benefits of various medical treatments

3、,procedures,and therapies.Cost effectiveness analysis(CEA)is the lesscontroversial part of HTA,because it is concernedwith measuring costs and benefits,not balancingthem against each other.Cost effectiveness analysisOften multiple treatments,with varying costs,can be used to treat a given disease.In

4、 such casesHow do insurance companies decide which treatments,if any,to provide coverage for?How do patients decide between an expensive and highly effective treatment and a low-cost treatment that is less effective?Cost effectiveness analysisIf one treatment is both cheaper and more effective than

5、a second treatment,then the second treatment is said to be dominated by the first.It is never optimal to use a dominated treatment,because there is always a more effective and cheaper alternative available.Cost effectiveness analysisIf neither treatment is dominant,one treatment must be both more ex

6、pensive and more effective.In such cases,cost-effectiveness analysis is used to help people decide whether the extra expenditure is worth it.Incremental cost-effectiveness ratio(ICER)Consider two treatments for the same disease:A and B.A is both more expensive and more effective than B,so neither tr

7、eatment dominates the other.The ICER of using A over B is:Lead poisoning exampleWhich treatment strategy is superior?Lead poisoning exampleThis ICER provides a price for avoiding a reading disability.In some sense,people can avoid a reading disability for an average price of$7,241.Note that the ICER

8、 does not make a determination about whether this is worth it or not,it is just an empirical fact about costs.The average cost-effectiveness ratio(ACER)Q:So why not just look at the various treatments ACERs and pick the one with the lowest cost per additional year of life?A:ACERs typically will not

9、reveal all the potentially cost-effective drugs.Ch 14|Health technology assessmentTHE COST EFFECTIVENESS FRONTIERCost-effectiveness frontier(CEF)Definition:a subset of treatment strategies for a condition that are not dominated by any other treatment.Any treatment on the CEF is said to be potentiall

10、y cost-effective.The CEF simplifies comparisons between treatments by allowing analysts to rule out dominated drugs(which should never be used),and focus only on options that potentially cost-effective.EX:Consider possible treatment options for the disease“bhtitis”:A,B,C,ICost-effectiveness frontier

11、(CEF)Cost-effectiveness frontier(CEF)Connect non-dominated options to form CEFThe slope of the CEF between two points is equal to the inverse of the ICER between the two.Cost-effectiveness frontier(CEF)Ch 14|Health technology assessmentMEASURING COSTSMeasuring costsIn order to calculate an ICER,we n

12、eed to measure the costs of each treatment.Whether a treatment is found to be cost-effective depends upon the perspective taken,because treatment costs and benefits differ for each party.The social planner perspective:all costs count.The patient perspective:only costs directly borne by patients coun

13、t.Which costs count?Suppose a complete course of a new lung cancer treatment costs$1,000.Is this the only cost to consider?What ifthe treatment must be administered in a distant location,or for extended periods of time?the treatment is uncomfortableor has unwanted side effects?the treatment will lea

14、d to adverse health effects in the future?Which costs count?How should future costs be counted?If lung-cancer patients are cured but then go on to have costly heart attacks,should those costs count against the treatment?There is active debate about which kinds of future costs should be included.Ch 1

15、4|Health technology assessmentMEASURING EFFECTIVENESSHow is“effectiveness”measured?One common measure of effectiveness is increased life expectancy.But how do we account for other health benefits that affect quality of life(e.g.increased mobility and freedom from pain)?The Quality-Adjusted Life Year

16、s(QALY)approach combines quality of life and life expectancy into a single index.QALYsIn a QALY calculation,each year of life receives a quality weight q between 0 and 1 that reflects the quality of that life-year.A year lived in perfect health has a quality of weight of q=1.Maybe a year with chroni

17、c cough and insomnia is only worth q=0.5,or a year confined to a wheelchair is only worth q=0.25.Who has the right to make this judgment?We will return to this questionQALEsCalculating QALYs requires estimating three pieces of information:the probability Pt of surviving to each year tthe quality of

18、life qt for each yeara time-discount rate(usually between 3%and 5%)A persons quality-adjusted life expectancy(QALE)is the number of additional years he expects to live,weighted by the discounted quality of his life in each of those years(i.e.the sum of his QALYs).Survey methods:quality weightsVisual

19、 analogue scale(VAS)asks respondents to rate health outcomes between 0(worst)and 100(best)Pros:simple to administer and easy for respondents to understand Cons:does not require respondents to think about tradeoffs between different health states.Thus,results may not reflect the intensity of responde

20、nts preferences.Survey methods:quality weightsStandard Gamble(SG):For health condition H,respondents choose between having H with certainty or a gamble with probability p of full health and probability(1-p)of death.The point of indifference between these two options is used as the quality weight q o

21、f health condition H.Pros:reflects intensity of preferences better than VAS.Cons:this approach may be affected by risk aversion,and people often respond in counterintuitive ways to such uncertain gambles.Pros:Reflects intensity of preferences better than VAS.Cons:may be biased if*is a function of ag

22、e Survey methods:quality weightsTime trade-off(TTO):respondents choose between 1)living for t years with a health state H before dying,and 2)living for a shorter amount of time in full health before dying.The quality weight q of health state H is the ratio*/t (with*representing the point of indiffer

23、ence between the two options).Whose opinion matters in QALY surveys?Healthy survey respondents may be unequipped to imagine the quality of life in health states they have not experienced.Expert panels are unlikely to ably represent patients preferences.People who have lived with a condition for deca

24、des tend to understate the suffering that healthy people would feel if they suddenly developed a condition(e.g.blindness).Ch 14|Health technology assessmentCOST-BENEFIT ANALYSIS:PICKING THE OPTIMAL TREATMENTCost-benefit analysis(CBA)Definition:Cost-benefit analysis(CBA)is the process of choosing an

25、optimal treatment among all potentially cost-effective ones,given a certain monetary value for each unit of health effect.This optimal treatment is then termed cost-effective for a person or agency with that valuation.When we place a monetary value on each QALY,we implicitly create a set of indiffer

26、ence curves that can be plotted with the CEF(why?)Example:Let us assume that a person values each QALY at$100,000.As a result,his indifference curves slope such that he is indifferent between one additional QALY and$100,000.We will revisit the crucial question of how to value life-years accurately.C

27、ost-benefit analysis(CBA)1)Plot the indifference curves2)Find the tangency point3)With these indifference curves,the cost-effective treatment is Drug C.Cost-benefit analysis(CBA)The impact of insuranceConsider the same situation,but now with an insurance package that covers 90%of drug costs.This ins

28、urance coverage lowers a patients out-of-pocket price per QALY.With insurance:Drug C now costs 10%of$160,000=$16,000 for 3 QALYsDrug H now costs 10%of$360,000=$36,000 for 3.4 QALYs.Moral hazard and HTAWith insurance,the person chooses Drug H,whereas without insurance,he would have opted for the chea

29、per Drug C.Moral hazard and HTAThe additional costs of Drug H are shared by every one in the patients insurance pool.Thus,insurance encourages technology overuse and the development of inefficient innovations.Given the problem of moral hazard,many insurance companies use rationing,in order to limit

30、such technology overuse.RationingDefinition:any method for allocating a scarce resource other than prices.Example:Insurance companies or national health systems may decline to pay for certain treatments that are not cost-effective.In the case of our CEF,the insurance company might decline to cover t

31、he expensive Drug H.As the insurance company is only willing to cover 90%of expenses for Drugs A and C,patients would likely respond by choosing Drug C.RationingWhile moving from to leads to worse health and fewer QALYs,the money saved on health care costs can now be spent elsewhere.Ch 14|Health tec

32、hnology assessmentVALUING LIFEEstimating the value of lifeThe CEF helps us find the best treatments for a given budget,but it does not indicate how much we should spend to obtain more life years or QALYs.In other words,how much is a QALY worth?To answer these questions,value of life estimates rely p

33、rimarily on three sources:labor market choices,product purchase decisions,and government policies.Estimating the value of lifeYou may think life cannot be valued economically or has an infinite value.Consider the following example:There is a suitcase across a busy street with a million dollars in it

34、.If you cross the busy street to get the suitcase,there is a 1%chance you will be struck by a bus and killed.Do you risk it?If you answer yes,your life cannot be worth more than$100 million to you($1 million divided by 0.01).Using the labor market to reveal VSL In order to attract workers to more ha

35、zardous jobs,high-risk employers offer additional wages(“risk premiums”),which supplement the wages workers would earn in comparable,but lower-risk jobs.If researchers know both the risk premium for a job and the difference in risks,then they can estimate how much a worker values his life.Example:A

36、worker who would take a job with a 1%higher fatal injury risk for$50,000 more in wages has a VSL of$50,000 0.01=$5 million.Using purchase decisions to reveal VSL Example:Jenkins et al.(2001)used price data for childrens bike helmets to estimate their VSLs.The decision to wear a helmet indicates a ju

37、dgment that the risk reduction of head trauma from bike accidents is worth the cost of buying helmets.Researchers used the prices of helmets to estimate a lower bound for the value of risk reduction and use that to calculate a lower bound for the VSL of helmet-wearers.Other purchasing decisions:smok

38、e detectors,safe cars vs unsafe cars.Using government policies to reveal VSL Example:In 1972,a U.S.law guaranteed kidney dialysis to all patients under 65 with end-stage renal disease for free.Kidney dialysis costs approximately$50,000 per QALY.The passage of this amendment suggests that a QALY is w

39、orth at least$50,000 to American taxpayers.ConclusionInsurers can neither cover every single new technology,nor refuse to cover all new proceduresInstead,most insurers are selective about which procedures to coverHTA is a tool that many insurers and national health systems use to make these coverage decisions In the policy lectures ahead,we will hear a lot more about HTA