《卫生经济学》课程参考文献（WHO年度报告）：World Health Report 2002_Reducing Risk Promoting Healthy Life_Chapter5 Some Strategies to Reduce Risk

CHAPTER FIVE Some strategies to Reduce risk This chapter puts forward the best available evidence on the cost and effec- tiveness of selected interventions to reduce some of the major risk factors dis- cussed in Chapter Four. It looks at the extent to which these interventions are likely to improve population health, both singly and in combination. It illus trates how decision-makers can begin the policy debate about priorities with information about which interventions would yield the greatest possible im provements in population health for the available resources. The chapter exam ines a range of strategies to reduce different types of risk, and the possible impact of those strategies on costs and effectiveness. Many risk reduction strategi involve a component of behaviour change, and some types of behaviour change might require active government intervention to succeed. Different ways of at- taining the same goal are discussed, for example, the population-wide versus the individual-based approach and prevention versus treatment With regard to policy implications, the chapter concludes that very substantial health gain can be made for relatively modest expenditures on interventions. However, the maximum possible gains for the resources that are available will be attained only through careful consideration of the costs and effects of interventions

Some Strategies to Reduce Risk 99 CHAPTER FIVE
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trategies to educe isk 99 This chapter puts forward the best available evidence on the cost and effec￾tiveness of selected interventions to reduce some of the major risk factors dis￾cussed in Chapter Four. It looks at the extent to which these interventions are likely to improve population health, both singly and in combination. It illus￾trates how decision-makers can begin the policy debate about priorities with information about which interventions would yield the greatest possible im￾provements in population health for the available resources. The chapter exam￾ines a range of strategies to reduce different types of risk, and the possible impact of those strategies on costs and effectiveness. Many risk reduction strategies involve a component of behaviour change, and some types of behaviour change might require active government intervention to succeed. Different ways of at￾taining the same goal are discussed, for example, the population-wide versus the individual-based approach and prevention versus treatment. With regard to policy implications, the chapter concludes that very substantial health gains can be made for relatively modest expenditures on interventions. However, the maximum possible gains for the resources that are available will be attained only through careful consideration of the costs and effects of interventions.

101 SOME STRATEGIES TO REDUCE RISK FROM HEALTH RISKS TO POLICY arlier chapters have quantified the burden of disease attributable to major risk factors, and shown the size of the potentially avoidable burden if the population distribution of risk is reduced across the board. This knowledge is important but it is only the first step required to decide how best to improve population health with the available resources.The second step involves assessing what types of intervention are available to decrease expo- sure to risks or to minimize the impact of exposure on health; to what extent they are likely to improve population health singly and in combination; and what resources are required to implement them. Chapter 4 quantified the importance of selected risk factors in different settings. This chapter evaluates selected interventions to reduce the impact on population health of some of those risk factors 1 Different types of evidence on intervention costs and effectiveness have been consid ered in the analysis detailed in this chapter. Some interventions have been widely imple mented in many settings, and relatively good information on their costs and effects exists. The interventions for which it is easier to obtain this type of evidence are often those that focus on individuals rather than on populations as a whole, and the overall impact on population health of such interventions can be relatively small. Some types of population based interventions with the potential to make very substantial improvements in popula tion health have not been implemented very frequently or have not been evaluated very often. The evidence on the costs and effectiveness of these interventions is less certain, but it is important to consider them because they have the potential to make very substantial differences in health outcomes Cost-effectiveness analysis can be undertaken in many ways and there have been sev- eral attempts to standardize methods to make results comparable(1-3). WHO has devel oped a standardized set of methods and tools that can be used to analyze the costs and population health impact of current and possible new interventions at the same time(3) As part of WHO,'s CHOiCe project, these tools and methods have been used to analyze a range of interventions that tackle some of the leading risks identified in Chapter 4.2 The ChoiCe project is intended to provide regularly updated databases on the costs and effects of a full range of promotive, preventive, curative and rehabilitative health This chapter represents a report on the first stage of a long-term work plan to evaluate the burden of all the major risks to health and the costs and effectiveness of all major interventions CHOICE stands for CHoosing Interventions that are Cost-Effective- see wwwwho int/evidence

Some Strategies to Reduce Risk 101 5 SOME STRATEGIES TO REDUCE RISK FROM HEALTH RISKS TO POLICY arlier chapters have quantified the burden of disease attributable to major risk factors, and shown the size of the potentially avoidable burden if the population distribution of risk is reduced across the board. This knowledge is important but it is only the first step required to decide how best to improve population health with the available resources. The second step involves assessing what types of intervention are available to decrease expo￾sure to risks or to minimize the impact of exposure on health; to what extent they are likely to improve population health singly and in combination; and what resources are required to implement them. Chapter 4 quantified the importance of selected risk factors in different settings. This chapter evaluates selected interventions to reduce the impact on population health of some of those risk factors.1 Different types of evidence on intervention costs and effectiveness have been consid￾ered in the analysis detailed in this chapter. Some interventions have been widely imple￾mented in many settings, and relatively good information on their costs and effects exists. The interventions for which it is easier to obtain this type of evidence are often those that focus on individuals rather than on populations as a whole, and the overall impact on population health of such interventions can be relatively small. Some types of population￾based interventions with the potential to make very substantial improvements in popula￾tion health have not been implemented very frequently or have not been evaluated very often. The evidence on the costs and effectiveness of these interventions is less certain, but it is important to consider them because they have the potential to make very substantial differences in health outcomes. Cost-effectiveness analysis can be undertaken in many ways and there have been sev￾eral attempts to standardize methods to make results comparable (1–3). WHO has devel￾oped a standardized set of methods and tools that can be used to analyze the costs and population health impact of current and possible new interventions at the same time (3). As part of WHO’s CHOICE project, these tools and methods have been used to analyze a range of interventions that tackle some of the leading risks identified in Chapter 4.2 The CHOICE project is intended to provide regularly updated databases on the costs and effects of a full range of promotive, preventive, curative and rehabilitative health interventions. 1 This chapter represents a report on the first stage of a long-term work plan to evaluate the burden of all the major risks to health and the costs and effectiveness of all major interventions. 2 CHOICE stands for CHoosing Interventions that are Cost-Effective – see www.who.int/evidence

102 The World Health Report 2002 To answer key policy questions on tackling risks to health, it is necessary to compare the costs and effectiveness of interventions to the situation that would exist if they were not done. This"counterfactualscenario-what would happen in the absence of the interven- tions against a particular risk factor-is different from the counterfactual used in Chapter 4 to estimate the avoidable burden of disease. There the question was what would the bur- den have been if the distribution of risks could be lowered by 25%, 50% or even 100%.That is useful in showing the relative importance of different risk factors, Table 5.1 Leading 10 selected risk factors as percent. but some of these risks can be reduced relatively easily, at low cost, age causes of disease burden measured in DALYs and others cannot. Because health resources are always scarce in re Developing countries lation to need choices must be made about how to allocate them between the substantial number of options available to reduce risks High mortality countries The best way of doing this is to estimate, for each intervention, the Unsafe 10.2%gans in population health and the associated costs compared to the Unsafe water, sanitation and hygiene 5.5% situation that would exist if the intervention were not undertaken. 3 Indoor smoke from solid fuels 3.7% This chapter reports the best available evidence on the cost and Zinc deficiency effectiveness of selected interventions to reduce some of the major Iron deficiency 3. 1% risk factors discussed in Chapter 4. The list of interventions is not Vitamin A deficiency 3.0% exhaustive and the chapter does not include all the risk factors of 2.5% Chapter 4. The ones for which interventions are considered here are 2.0% highlighted in bold type in Table 5.1. A more comprehensive picture 1.9% of interventions concerning diseases as well as additional risk factors Low mortality countries (e.g. alcohol)will be presented in The World Health report 2003 Alcohol 6.29 The analysis is used to identify some interventions that are very Blood pressure 5.0% cost-effective and some that are not cost-effective in different set- Tobacco 4.0% tings It illustrates how decision-makers can begin the policy debate derweight 3.1% about priorities for allocating health resources with information about 7% which interventions have the potential to yield substantial improve 2.1% ments in population health for the available resources. Indoor smoke from solid fuels 1.9% is evidence will be only one input to the final decision about Low fruit and vegetable intake the best combination of interventions. Improving population health Iron deficiency 1.8% is the defining goal of health systems, but there are other social goals Insafe water, sanitation and hygiene 1.79 to which health systems contribute Policy-makers will wish to con- Developed countries sider the impact of different combinations of interventions on health inequalities and poverty and on the responsiveness of their systems, Blood pressure 12. 2%6 for example(4). Communities in different settings might differ in Cholesterol 7. 6%activities, and particular activities might be more difficult to incorpo- 7 49 rate into existing health system infrastructure in some settings than ow fruit and vegetable intake 3.9% in others. The information from this chapter is, therefore, one input Physical inactivity 3.3% a key one, but not the only one-to the policy debate. llicit drugs The analysis does not apply simply to interventions funded by Unsafe sex 0.8% government WHO argues that governments should be good stew- 0.7% ards of their health systems(5). If the population uses interventions Risk factors discussed in this chapter are in bold type that are ineffective, dangerous, or are simply not good value for money, 3 The term"intervention"is used in this chapter in a very broad sense. It includes any health action-any motive, preventive, curative or rehabilitative activity where the primary intent is to improve health. nterventions in the chapter range from the introduction of a tax on tobacco products to treating hyp tension to prevent a heart attack

102 The World Health Report 2002 To answer key policy questions on tackling risks to health, it is necessary to compare the costs and effectiveness of interventions to the situation that would exist if they were not done. This “counterfactual” scenario – what would happen in the absence of the interven￾tions against a particular risk factor – is different from the counterfactual used in Chapter 4 to estimate the avoidable burden of disease. There the question was what would the bur￾den have been if the distribution of risks could be lowered by 25%, 50% or even 100%. That is useful in showing the relative importance of different risk factors, but some of these risks can be reduced relatively easily, at low cost, and others cannot. Because health resources are always scarce in re￾lation to need, choices must be made about how to allocate them between the substantial number of options available to reduce risks. The best way of doing this is to estimate, for each intervention, the gains in population health and the associated costs compared to the situation that would exist if the intervention were not undertaken.3 This chapter reports the best available evidence on the cost and effectiveness of selected interventions to reduce some of the major risk factors discussed in Chapter 4. The list of interventions is not exhaustive and the chapter does not include all the risk factors of Chapter 4. The ones for which interventions are considered here are highlighted in bold type in Table 5.1. A more comprehensive picture of interventions concerning diseases as well as additional risk factors (e.g. alcohol) will be presented in The World Health Report 2003. The analysis is used to identify some interventions that are very cost-effective and some that are not cost-effective in different set￾tings. It illustrates how decision-makers can begin the policy debate about priorities for allocating health resources with information about which interventions have the potential to yield substantial improve￾ments in population health for the available resources. This evidence will be only one input to the final decision about the best combination of interventions. Improving population health is the defining goal of health systems, but there are other social goals to which health systems contribute. Policy-makers will wish to con￾sider the impact of different combinations of interventions on health inequalities and poverty and on the responsiveness of their systems, for example (4). Communities in different settings might differ in their ability and willingness to participate in specific risk-reduction activities, and particular activities might be more difficult to incorpo￾rate into existing health system infrastructure in some settings than in others. The information from this chapter is, therefore, one input – a key one, but not the only one – to the policy debate. The analysis does not apply simply to interventions funded by government. WHO argues that governments should be good stew￾ards of their health systems (5). If the population uses interventions that are ineffective, dangerous, or are simply not good value for money, 3 The term “intervention” is used in this chapter in a very broad sense. It includes any health action – any promotive, preventive, curative or rehabilitative activity where the primary intent is to improve health. Interventions in the chapter range from the introduction of a tax on tobacco products to treating hyper￾tension to prevent a heart attack. Table 5.1 Leading 10 selected risk factors as percent￾age causes of disease burden measured in DALYsa Developing countries High mortality countries Underweight 14.9% Unsafe sex 10.2% Unsafe water, sanitation and hygiene 5.5% Indoor smoke from solid fuels 3.7% Zinc deficiency 3.2% Iron deficiency 3.1% Vitamin A deficiency 3.0% Blood pressure 2.5% Tobacco 2.0% Cholesterol 1.9% Low mortality countries Alcohol 6.2% Blood pressure 5.0% Tobacco 4.0% Underweight 3.1% Overweight 2.7% Cholesterol 2.1% Indoor smoke from solid fuels 1.9% Low fruit and vegetable intake 1.9% Iron deficiency 1.8% Unsafe water, sanitation and hygiene 1.7% Developed countries Tobacco 12.2% Blood pressure 10.9% Alcohol 9.2% Cholesterol 7.6% Overweight 7.4% Low fruit and vegetable intake 3.9% Physical inactivity 3.3% Illicit drugs 1.8% Unsafe sex 0.8% Iron deficiency 0.7% a Risk factors discussed in this chapter are in bold type

Some Strategies to Reduce Risk 103 governments should find ways to encourage people to use resources more appropriately even if the finance is not provided by govemment. The evidence presented in this chapter will facilitate this process WHAT STRATEGIES CAN REDUCE RISKS TO HEALTH? WHO defines the health system to include all actions whose primary intent is to im prove health(5) and some activities that improve health fall outside this definition Exam- ples include reductions in poverty, and improvements in housing and education, which may well reduce exposures to some types of risks but are not primarily designed to improve health. This chapter is concerned mainly with interventions that have the primary intent of proving health. Some interventions, however, are difficult to categorize strictly using this definition. One set that has traditionally fallen within the remit of public health covers improvements to water and sanitation. Many water and sanitation programmes fall outside the health por folio, and clearly such improvements do have considerable amenity value outside health. However, clean water and improved sanitation are considered in this chapter because their attributable burden of disease is so significant. It must be noted, however, that althor they improve health, many of their benefits are not readily incorporated into a cost-effec- tiveness framework and should be considered when comparing them with other types of A number of strategies have been used to reduce health risks that are seen as modifi- able. They can be categorized broadly as interventions that seek to reduce risks in the popu lation as a whole, and those which target individuals within the population. The former include intervention by governments through legislation, tax or financial incentives; engi neering solutions such as the introduction of safety belts in motor vehicles or the provision of piped water; and health promotion campaigns targeting the general public. The latter clude strategies to change health behaviours of individuals, often through personal inter- action with a health provider; and strategies to change the behaviours of health providers, particularly in the way they interact with their clients Genetic screening is a valuable tool for some diseases associated with the risk factors described in this report, but individual genes are not susceptible to m Genetic screening is not considered further in this chapter. RISK REDUCTION AND BEHAVIOUR Many risk reduction strategies involve a component of behaviour change. Even engi neering solutions, such as the provision of piped drinking-water, will not result in health improvements unless people are willing to use the new source. Social scientists argue that behavioural change first requires understanding(6, 7).4 Anumber of individual preferences or characteristics influence how people translate understanding into health behaviours, including how averse to health risks individuals are and how they value possible future health decrements compared with other competing choices in their lives such as wealth and lifestyle. These preferences are influenced by information and the influence of adver- Perceived risk "is the subjective assessment of personal disease risk, based on an indi viduals interpretation of epidemiological and other types of data. There may be a difference In the case of addiction, individuals can struggle to change their behaviours despite recognition of the harmful effects to themselves and others( 8)

Some Strategies to Reduce Risk 103 governments should find ways to encourage people to use resources more appropriately even if the finance is not provided by government. The evidence presented in this chapter will facilitate this process. WHAT STRATEGIES CAN REDUCE RISKS TO HEALTH? WHO defines the health system to include all actions whose primary intent is to im￾prove health (5) and some activities that improve health fall outside this definition. Exam￾ples include reductions in poverty, and improvements in housing and education, which may well reduce exposures to some types of risks but are not primarily designed to improve health. This chapter is concerned mainly with interventions that have the primary intent of improving health. Some interventions, however, are difficult to categorize strictly using this definition. One set that has traditionally fallen within the remit of public health covers improvements to water and sanitation. Many water and sanitation programmes fall outside the health port￾folio, and clearly such improvements do have considerable amenity value outside health. However, clean water and improved sanitation are considered in this chapter because their attributable burden of disease is so significant. It must be noted, however, that although they improve health, many of their benefits are not readily incorporated into a cost-effec￾tiveness framework and should be considered when comparing them with other types of health interventions. A number of strategies have been used to reduce health risks that are seen as modifi￾able. They can be categorized broadly as interventions that seek to reduce risks in the popu￾lation as a whole, and those which target individuals within the population. The former include intervention by governments through legislation, tax or financial incentives; engi￾neering solutions such as the introduction of safety belts in motor vehicles or the provision of piped water; and health promotion campaigns targeting the general public. The latter include strategies to change health behaviours of individuals, often through personal inter￾action with a health provider; and strategies to change the behaviours of health providers, particularly in the way they interact with their clients. Genetic screening is a valuable tool for some diseases associated with the risk factors described in this report, but individual genes are not susceptible to manipulation at present. Genetic screening is not considered further in this chapter. RISK REDUCTION AND BEHAVIOUR Many risk reduction strategies involve a component of behaviour change. Even engi￾neering solutions, such as the provision of piped drinking-water, will not result in health improvements unless people are willing to use the new source. Social scientists argue that behavioural change first requires understanding (6, 7). 4A number of individual preferences or characteristics influence how people translate understanding into health behaviours, including how averse to health risks individuals are and how they value possible future health decrements compared with other competing choices in their lives such as wealth and lifestyle. These preferences are influenced by information and the influence of adver￾tising and marketing. “Perceived risk” is the subjective assessment of personal disease risk, based on an indi￾vidual’s interpretation of epidemiological and other types of data. There may be a difference 4 In the case of addiction, individuals can struggle to change their behaviours despite recognition of the harmful effects to themselves and others (8)

104 The World Health Report 2002 between risk perception as an individual and cultural concepts of risk acceptability by soci ty. For example, although driving without a seat belt may be deemed so unacceptable by a ociety that legislation is enacted to enforce it, individuals within that society may perceive the risk to themselves as trivial and choose not to use a seat belt When it comes to risks to health, individuals and societies sometimes prefer to enjoy the benefits of an activity now without thinking about possible future health costs. High con- sumption of certain types of food, for instance, is perceived by some people to give current pleasure despite the risk of harmful health effects-to which they give less weight because they will occur in the future. There is considerable variation in the rate at which people events that might happen in the future. Some research has indicated that smokers"dis- count the future"more highly than non-smokers-for example, a given probability of de veloping lung cancer in 20 years is given less weight by smokers than by non-smokers(9) People who discount the future more highly value a given future health risk less highly than people who discount the future less highly, even if they have the same information The question of how technically to incorporate this into the analysis is discussed later but the effectiveness of behavioural modification interventions is clearly influenced by varia- tions in how people perceive the future A set of additional factors also influences the way people respond to risk-reduction interventions. Even when people have heard and understood the message that insecticide treated nets prevent mosquito bites, and wish to use them to avoid both the nuisance value of mosquitoes and the risk of malaria, a number of factors may prevent them from doing so (10). These include the availability and affordability of nets in their locale and their sleeping arrangements(in a house, or on the street). These in turn will be affected by many factors including personal, community and health system characteristics. One determinant is culture and the social support networks available, sometimes called tem is financed(for example, through social health insurance or user charges)or organized (for example, through managed care or a publicly funded system), also influence beha iours and, through them, the costs and effectiveness of interventions INDIVIDUAL- BASED VERSUS POPULATION APPROACHE TO RISK REDUCTION Two broad approaches to reducing risk were defined earlier. The first is to focus the intervention on the people likely to benefit, or benefit most, from it. The second is to seek to reduce risks in the entire population regardless of each individual's level of risk and poten tial benefits. In some cases, both approaches could be used at the same time. Focusing on high-risk individuals can reduce costs at the population level because an intervention is provided to fewer people, but on the other hand it might also increase the costs of identify the of peop likely to ber Focusing on people who are more likely to benefit has a significant impact on the healtl of a nation only when there are large numbers of them. For example, lowering cholesterol with drugs is effective in reducing overall mortality in a group of people at high risk of leath from heart disease; targeting interventions to reduce cholesterol to the needs of these people focuses the interventions on a group of people likely to benefit. However, only a small percentage of the population is at high risk of death from heart disease at any given time, and only some of them can be identified purely on the basis of

104 The World Health Report 2002 between risk perception as an individual and cultural concepts of risk acceptability by soci￾ety. For example, although driving without a seat belt may be deemed so unacceptable by a society that legislation is enacted to enforce it, individuals within that society may perceive the risk to themselves as trivial and choose not to use a seat belt. When it comes to risks to health, individuals and societies sometimes prefer to enjoy the benefits of an activity now without thinking about possible future health costs. High con￾sumption of certain types of food, for instance, is perceived by some people to give current pleasure despite the risk of harmful health effects – to which they give less weight because they will occur in the future. There is considerable variation in the rate at which people value and assess adverse events that might happen in the future. Some research has indicated that smokers “dis￾count the future” more highly than non-smokers – for example, a given probability of de￾veloping lung cancer in 20 years is given less weight by smokers than by non-smokers (9). People who discount the future more highly value a given future health risk less highly than people who discount the future less highly, even if they have the same information. The question of how technically to incorporate this into the analysis is discussed later but the effectiveness of behavioural modification interventions is clearly influenced by varia￾tions in how people perceive the future. A set of additional factors also influences the way people respond to risk-reduction interventions. Even when people have heard and understood the message that insecticide￾treated nets prevent mosquito bites, and wish to use them to avoid both the nuisance value of mosquitoes and the risk of malaria, a number of factors may prevent them from doing so (10). These include the availability and affordability of nets in their locale and their sleeping arrangements (in a house, or on the street). These in turn will be affected by many factors including personal, community and health system characteristics. One determinant is culture and the social support networks available, sometimes called social capital. Health system and provider characteristics, such as the way the health sys￾tem is financed (for example, through social health insurance or user charges) or organized (for example, through managed care or a publicly funded system), also influence behav￾iours and, through them, the costs and effectiveness of interventions. INDIVIDUAL-BASED VERSUS POPULATION APPROACHES TO RISK REDUCTION Two broad approaches to reducing risk were defined earlier. The first is to focus the intervention on the people likely to benefit, or benefit most, from it. The second is to seek to reduce risks in the entire population regardless of each individual’s level of risk and poten￾tial benefits. In some cases, both approaches could be used at the same time. Focusing on high-risk individuals can reduce costs at the population level because an intervention is provided to fewer people, but on the other hand it might also increase the costs of identify￾ing the group of people most likely to benefit. Focusing on people who are more likely to benefit has a significant impact on the health of a nation only when there are large numbers of them. For example, lowering cholesterol with drugs is effective in reducing overall mortality in a group of people at high risk of death from heart disease; targeting interventions to reduce cholesterol to the needs of these people focuses the interventions on a group of people likely to benefit. However, only a small percentage of the population is at high risk of death from heart disease at any given time, and only some of them can be identified purely on the basis of their cholesterol levels. Recent evidence suggests that the group most likely to benefit from

Some Strategies to Reduce Risk cholesterol reduction consists of individuals with combinations of risk factors, such as be- g male, with ischaemic changes, who smoke, are obese, are not physically active and have high blood pressure and high cholesterol (11). Designing interventions for people with a combination of those risk factors might well prove to be more effective than treating people only on the basis of their levels of cholesterol(12). This form of targeted approach will sequently be called the"absolute risk approach The high-risk approach can be viewed as targeting the right-hand tail of the risk factor curves in Figure 5.1(13). The alternative is to try to shift the entire population distribution of risk factors to the left -like shifting the distribution of blood pressure for London civil servants in the direction of that of Kenyan nomads. This has the potential to improve popu lation health to a much greater extent than a high-risk approach, while at the same time reducing the costs of identifying high-risk people. On the other hand, the costs of provid ng an intervention to the entire population would, in this case, be higher than providing it only to people in the right-hand tail. Which approach is the most cost-effective in any setting will depend on the prevalence of high-risk people in the population and the costs of identifying them compared with the costs of the available blood pressure reduction THE ROLE OF GOVERNMENT AND LEGISLATION Some areas of behavioural change are likely to be adopted relatively easily once infor- mation becomes available, assuming that the technology is affordable. Other types of be havioural change will benefit from active government intervention, particularly those where people have high rates of time discount or low rates of risk aversion. Government action is required if the full potential to improve population health through the reduction of alcohol substances. Such. mption is to be achieved, partly because of the addictive nature of these and tobacco con action could be through changes in the law or financial incentives and disincentives. Road safety is another area where a significant number of people might not Figure 5.1 Distributions of systolic blood pressure in middle-aged men in two populations nomads 80 Source: Rose G Sick individuals and sick populations. Intermational Journal of Epidemiology 1985: 14:32-8

Some Strategies to Reduce Risk 105 cholesterol reduction consists of individuals with combinations of risk factors, such as be￾ing male, with ischaemic changes, who smoke, are obese, are not physically active and have high blood pressure and high cholesterol (11). Designing interventions for people with a combination of those risk factors might well prove to be more effective than treating people only on the basis of their levels of cholesterol (12). This form of targeted approach will subsequently be called the “absolute risk approach”. The high-risk approach can be viewed as targeting the right-hand tail of the risk factor curves in Figure 5.1 (13). The alternative is to try to shift the entire population distribution of risk factors to the left – like shifting the distribution of blood pressure for London civil servants in the direction of that of Kenyan nomads. This has the potential to improve popu￾lation health to a much greater extent than a high-risk approach, while at the same time reducing the costs of identifying high-risk people. On the other hand, the costs of provid￾ing an intervention to the entire population would, in this case, be higher than providing it only to people in the right-hand tail. Which approach is the most cost-effective in any setting will depend on the prevalence of high-risk people in the population and the costs of identifying them compared with the costs of the available blood pressure reduction strategies. THE ROLE OF GOVERNMENT AND LEGISLATION Some areas of behavioural change are likely to be adopted relatively easily once infor￾mation becomes available, assuming that the technology is affordable. Other types of be￾havioural change will benefit from active government intervention, particularly those where people have high rates of time discount or low rates of risk aversion. Government action is required if the full potential to improve population health through the reduction of alcohol and tobacco consumption is to be achieved, partly because of the addictive nature of these substances. Such action could be through changes in the law or financial incentives and disincentives. Road safety is another area where a significant number of people might not Source: Rose G. Sick individuals and sick populations. International Journal of Epidemiology 1985; 14:32-8. 0 10 20 30 40 60 80 100 120 140 160 180 200 Systolic blood pressure (mmHg) Population (%) Kenyan nomads London civil servants Figure 5.1 Distributions of systolic blood pressure in middle-aged men in two populations

106 The World Health Report 2002 choose to drive safely, or use seat belts or motorcycle helmets, but government action can encourage them to do so, thereby preventing injuries to themselves and to other people. Increasing prices through taxation certainly reduces smoking (14)even if smuggling increases subsequently(15). A particular focus of this chapter is to explore if this type of government action is cost-effective. In some countries there has been debate about whether governments should play this type of role, and information on the costs and impact on population health are important inputs to this debate. DIFFERENT WAYS OF ATTAINING THE SAME GOAL Different sets of interventions can be used to achieve the same goal and some interven tions will reduce the burden associated with multiple risk factors and diseases. Interven- tions to reduce blood pressure, cigarette smoking and cholesterol all reduce cardiovascular disease, and each has been used separately and together with others at different times and in different settings. The effect of doing two at the same time might be more than would be expected by adding the benefits of doing the two interventions singly, or might be less Much ischaemic heart disease mortality that has traditionally been attributed to particular sk factors is, in fact, caused by those factors in combination with other risk factors(16) Partly as a result of these interactions, risk reduction strategies are generally based on a ombination of interventions rather than just one The decision about which combination should be undertaken for the available resources complex. It is necessary to determine the health gains, and the costs, of doing each pos sible intervention by itself and in combination with the other ways of reducing the burden for a given risk factor or disease. The analysis undertaken for this chapter followed that process by evaluating what would be achieved by each intervention alone and in combina tion with other interventions TECHNICAL CONSIDERATIONS FOR COST-EFFECTIVENESS ANALYSIS The estimates, which provide the basis of the results reported in this chapter, were un- dertaken on a regional basis as part of the WHO CHOICe project. The six WHO regions were divided into mortality strata as described in earlier chapters, resulting in 14 epidemio- logical subregions. The total costs and total effects of each intervention were estimated separately for the 14 subregions. Eventually it is hoped that there will be sufficient data to make estimates at a country level, and even at the subnational level for large countries, but this is not currently possible Subregional analysis offers a valuable basis from which country analysts can work to calibrate the results to their settings. It is much more policy-relevant than a global analysis because the epidemiology, cost structures, and starting points (such as the availability of trained health staff and the history of health interventions)varies less within each subregion than across the world as a whole. The results are used here to identify interventions that are ery cost-effective, cost-effective, and not cost-effective in each subregion. Costs are reported in terms of intermational dollars rather than in US dollars, to account better for differences in cost structures between settings. Unit costs for most regions are higher using international dollars(s) based on purchasing power parity exchange rates than they would be if official exchange rates had been used. Effectiveness is measured in terms of disability-adjusted life years(DALYs) gained by the intervention. A brief descrip

106 The World Health Report 2002 choose to drive safely, or use seat belts or motorcycle helmets, but government action can encourage them to do so, thereby preventing injuries to themselves and to other people. Increasing prices through taxation certainly reduces smoking (14) even if smuggling increases subsequently (15). A particular focus of this chapter is to explore if this type of government action is cost-effective. In some countries there has been debate about whether governments should play this type of role, and information on the costs and impact on population health are important inputs to this debate. DIFFERENT WAYS OF ATTAINING THE SAME GOAL Different sets of interventions can be used to achieve the same goal and some interven￾tions will reduce the burden associated with multiple risk factors and diseases. Interven￾tions to reduce blood pressure, cigarette smoking and cholesterol all reduce cardiovascular disease, and each has been used separately and together with others at different times and in different settings. The effect of doing two at the same time might be more than would be expected by adding the benefits of doing the two interventions singly, or might be less. Much ischaemic heart disease mortality that has traditionally been attributed to particular risk factors is, in fact, caused by those factors in combination with other risk factors (16). Partly as a result of these interactions, risk reduction strategies are generally based on a combination of interventions rather than just one. The decision about which combination should be undertaken for the available resources is complex. It is necessary to determine the health gains, and the costs, of doing each pos￾sible intervention by itself and in combination with the other ways of reducing the burden for a given risk factor or disease. The analysis undertaken for this chapter followed that process by evaluating what would be achieved by each intervention alone and in combina￾tion with other interventions. TECHNICAL CONSIDERATIONS FOR COST-EFFECTIVENESS ANALYSIS The estimates, which provide the basis of the results reported in this chapter, were un￾dertaken on a regional basis as part of the WHO CHOICE project. The six WHO regions were divided into mortality strata as described in earlier chapters, resulting in 14 epidemio￾logical subregions. The total costs and total effects of each intervention were estimated separately for the 14 subregions. Eventually it is hoped that there will be sufficient data to make estimates at a country level, and even at the subnational level for large countries, but this is not currently possible. Subregional analysis offers a valuable basis from which country analysts can work to calibrate the results to their settings. It is much more policy-relevant than a global analysis because the epidemiology, cost structures, and starting points (such as the availability of trained health staff and the history of health interventions) varies less within each subregion than across the world as a whole. The results are used here to identify interventions that are very cost-effective, cost-effective, and not cost-effective in each subregion. Costs are reported in terms of international dollars rather than in US dollars, to account better for differences in cost structures between settings. Unit costs for most regions are higher using international dollars (I$) based on purchasing power parity exchange rates than they would be if official exchange rates had been used.5 Effectiveness is measured in terms of disability-adjusted life years (DALYs) gained by the intervention. A brief descrip-

Some Strategies to Reduce Risk tion of the methods is found in box 5.1, while full details of the methods and the calcula tions can be found on the WHo web site. 6 It is not much value to provide decision-makers with information on the costs and effectiveness of interventions that are undertaken badly. Accordingly, the results reported here show what would be achieved if the interventions were undertaken in a relatively efficient manner. For example, we assume capacity utilization of 80% in most settings -for example, staff and capital equipment are fully occupied for 80% of the normal working day except when estimating the effect of expanding coverage to very high levels. To reach% of the population it might be necessary to provide facilities in isolated areas where popula tion numbers are insufficient to support such high rates of capacity utilization.The results, therefore, provide guidance on selected interventions that should be given high priority in the policy debate about resource allocation, but only if they are undertaken in an efficient manner Sets of interventions that interact in terms of effectiveness or costs are considered to gether, as stated earlier. For example, interventions to reduce risks associated with hyper- tension and high cholesterol interact. The analysis is based on estimates of the effects on population health of reducing blood pressure alone, reducing cholesterol levels alone, and doing both toget In addition, many of the interventions are evaluated at different levels of coverage. For most, three levels were used (50%, 80%and 95%)and the impact on costs and effects of expanding coverage was incorporated The standard practice in this type of analysis is to discount both the health effects and the costs of the different programmes under consideration. There is no controversy about 5.1 Methods for cost-effectiveness analysis The cost-effectiveness analysis on which this terventions or combinations of interventions. For quantities of inputs required to run each inte reportis based considered what would have hap- example, based on data from earlier chapters, vi- vention were estimated by experts in 17 regions ned if a set of interventions had not been tamin A deficiency increases the risk of dying from of the world and validated against the literature implemented and compared the result with what diarrhoea. The impact of vitamin A supplementa- Some individual-level costs were obtained by happens on their implementation. Through a tion is then mediated in the model by a decrea multiplying unit costs of inputs by the expected four-state population model, the number of in case fatality rate for diarrhoea Effectiveness data utilization of those inputs by the people covered ed over a period of a hun- came from systematic reviews where available. The by the programme. Unit costs for outpatient vis- dred years by a population in the absence of that difference in the healthy life years gained by the its and laboratory tests were obtained from a set of interventions is estimated by inputting population with and without the intervention is review of literature and supplemented by pri parameters of incidence, remission, cause-spe- the impact of the intervention and is entered as mary data from several countries. The total costs valuations reflecting the natural history of the Costs covered in this analysis indude expenses stitutes the denominator of the cost-effective- disease. The parameters reflecting the natural associated with running the intervention, such as ness ratio history of the disease were mostly estimated by administration, training and contact with the me- Stochastic uncertainty analysis was carried back-adjusting current rates using coverage and dia. They also indude costs incurred at the indi- out for key parameters in both the numerator known effectiveness of interventions. The same vidual level such as counselling. Considerableeffort and denominator four-state population model can then be rerun, was exerted to try to standardize the methodol reflecting changes in the parameters due to in- ogy used in collecting and classifying costs. The Sources: (3, 17-19). 5 This is important to keep in mind when benchmarking the estimates in this chapter against those re- sewhere, usually in US dollars. International dollars are derived by dividin by an estimate of their purchasing power parity(PPP)compared to a USS PPPs are the rates of currency onversion that equalize the purchasing power of different currencies by eliminating the differences in s price levels between countries

Some Strategies to Reduce Risk 107 tion of the methods is found in Box 5.1, while full details of the methods and the calcula￾tions can be found on the WHO web site.6 It is not much value to provide decision-makers with information on the costs and effectiveness of interventions that are undertaken badly. Accordingly, the results reported here show what would be achieved if the interventions were undertaken in a relatively efficient manner. For example, we assume capacity utilization of 80% in most settings – for example, staff and capital equipment are fully occupied for 80% of the normal working day – except when estimating the effect of expanding coverage to very high levels. To reach 95% of the population it might be necessary to provide facilities in isolated areas where popula￾tion numbers are insufficient to support such high rates of capacity utilization. The results, therefore, provide guidance on selected interventions that should be given high priority in the policy debate about resource allocation, but only if they are undertaken in an efficient manner. Sets of interventions that interact in terms of effectiveness or costs are considered to￾gether, as stated earlier. For example, interventions to reduce risks associated with hyper￾tension and high cholesterol interact. The analysis is based on estimates of the effects on population health of reducing blood pressure alone, reducing cholesterol levels alone, and doing both together. In addition, many of the interventions are evaluated at different levels of coverage. For most, three levels were used (50%, 80% and 95%) and the impact on costs and effects of expanding coverage was incorporated. The standard practice in this type of analysis is to discount both the health effects and the costs of the different programmes under consideration. There is no controversy about 5 This is important to keep in mind when benchmarking the estimates in this chapter against those re￾ported elsewhere, usually in US dollars. International dollars are derived by dividing local currency units by an estimate of their purchasing power parity (PPP) compared to a US$. PPPs are the rates of currency conversion that equalize the purchasing power of different currencies by eliminating the differences in price levels between countries. 6 www.who.int/evidence Box 5.1 Methods for cost-effectiveness analysis The cost-effectiveness analysis on which this report is based considered what would have hap￾pened if a set of interventions had not been implemented and compared the result with what happens on their implementation. Through a four-state population model, the number of healthy life years lived over a period of a hun￾dred years by a population in the absence of that set of interventions is estimated by inputting parameters of incidence, remission, cause-spe￾cific and background mortality, and health state valuations reflecting the natural history of the disease. The parameters reflecting the natural history of the disease were mostly estimated by back-adjusting current rates using coverage and known effectiveness of interventions. The same four-state population model can then be rerun, reflecting changes in the parameters due to in￾quantities of inputs required to run each inter￾vention were estimated by experts in 17 regions of the world and validated against the literature. Some individual-level costs were obtained by multiplying unit costs of inputs by the expected utilization of those inputs by the people covered by the programme. Unit costs for outpatient vis￾its and laboratory tests were obtained from a review of literature and supplemented by pri￾mary data from several countries. The total costs for implementing a programme for 10 years con￾stitutes the denominator of the cost-effective￾ness ratio. Stochastic uncertainty analysis was carried out for key parameters in both the numerator and denominator. terventions or combinations of interventions. For example, based on data from earlier chapters, vi￾tamin A deficiency increases the risk of dying from diarrhoea. The impact of vitamin A supplementa￾tion is then mediated in the model by a decrease in case fatality rate for diarrhoea. Effectiveness data came from systematic reviews where available. The difference in the healthy life years gained by the population with and without the intervention is the impact of the intervention and is entered as the denominator of the cost-effectiveness ratio. Costs covered in this analysis include expenses associated with running the intervention, such as administration, training and contact with the me￾dia. They also include costs incurred at the indi￾vidual level such as counselling. Considerable effort was exerted to try to standardize the methodol￾ogy used in collecting and classifying costs. The Sources: (3, 17–19)

108 The World Health Report 2002 the appropriate discount rate to use for costs: the opportunity cost of capital. The discount rate for benefits is often thought to comprise two parts. One is a"pure"time preference for immediate over postponed consumption. The second relates to the fact that, as the pros- perity of a society increases, the utility or benefit to it of a defined unit of consumption is less-that is, there is declining marginal utility of a unit of consumption as income rises Many cost-effectiveness studies have assumed that this applies to health benefits as well and have discounted future health at a rate between 3% and 5% per year. This practice has long been debated, and some people have argued that the discount rate for health benefits should be close to zero and certainly less than the discount rate for costs (20-22) This question is important for the analysis in the following section as it can change the relative priority of interventions. Not all health care programmes achieve results at the same rate. Public health and health promotion programmes in particular may take many years to produce tangible results, and applying a discount rate to the benefits of such pro- grammes will reduce their apparent attractiveness compared with programmes that pro- duce rapid benefits of a similar magnitude Common practice remains to discount costs and benefits at the same rate, so we follow the same practice in our baseline calculations using a rate of 3%.To be consistent with the approach used in Chapter 4 for measuring the burden of disease, age weights are also included in the baseline calculations The recent report of the Commission on Macroeconomics and Health suggested that interventions costing less than three times gDP per capita for each DALY averted repre sent good value for money and that, if a country could not afford to undertake them all from its own resources, the international community should find ways of supporting them (23). This report's classification of interventions is based on this principle, and defines very cost-effective interventions as those which avert each additional daly at a cost less than GDP per capita, and cost-effective interventions as those where each DALY averted costs between one and three times GDP per capita. Finally, cost-effectiveness analyses can be found in the published literature for some of e interventions discussed in this chapter, which does not, however, simply report the published results. The methods used for estimating costs and effectiveness varies consider- ably across the published studies and their results cannot be compared. Moreover, most provide insufficient information on how they estimated costs to be sure that all possibl costs were included and valued appropriately. This report, therefore, re-estimated costs and effects using a standard approach for all interventions, although each study that could be found was evaluated to determine if the parameters it used could be incorporated CHOOSING INTERVENTIONS TO REDUCE SPECIFIC RISKS The results reported in this chapter are important inputs to two types of policy ques tions.The first is how best to reduce the health burden associated with a specific risk facto where information on the effectiveness and costs of the alternative interventions is one crucial input. The second is how best to reduce the health burden associated with risk factors in general, where information on the effectiveness and costs of interventions aimed as a variety of risk factors is critical. This section covers the first question, by reviewing the cost-effectiveness of selected interventions aimed at some of the main risk factors described

108 The World Health Report 2002 the appropriate discount rate to use for costs: the opportunity cost of capital. The discount rate for benefits is often thought to comprise two parts. One is a “pure” time preference for immediate over postponed consumption. The second relates to the fact that, as the pros￾perity of a society increases, the utility or benefit to it of a defined unit of consumption is less – that is, there is declining marginal utility of a unit of consumption as income rises. Many cost-effectiveness studies have assumed that this applies to health benefits as well and have discounted future health at a rate between 3% and 5% per year. This practice has long been debated, and some people have argued that the discount rate for health benefits should be close to zero and certainly less than the discount rate for costs (20–22). This question is important for the analysis in the following section as it can change the relative priority of interventions. Not all health care programmes achieve results at the same rate. Public health and health promotion programmes in particular may take many years to produce tangible results, and applying a discount rate to the benefits of such pro￾grammes will reduce their apparent attractiveness compared with programmes that pro￾duce rapid benefits of a similar magnitude. Common practice remains to discount costs and benefits at the same rate, so we follow the same practice in our baseline calculations using a rate of 3%. To be consistent with the approach used in Chapter 4 for measuring the burden of disease, age weights are also included in the baseline calculations. The recent report of the Commission on Macroeconomics and Health suggested that interventions costing less than three times GDP per capita for each DALY averted repre￾sent good value for money and that, if a country could not afford to undertake them all from its own resources, the international community should find ways of supporting them (23). This report’s classification of interventions is based on this principle, and defines very cost-effective interventions as those which avert each additional DALY at a cost less than GDP per capita, and cost-effective interventions as those where each DALY averted costs between one and three times GDP per capita. Finally, cost-effectiveness analyses can be found in the published literature for some of the interventions discussed in this chapter, which does not, however, simply report the published results. The methods used for estimating costs and effectiveness varies consider￾ably across the published studies and their results cannot be compared. Moreover, most provide insufficient information on how they estimated costs to be sure that all possible costs were included and valued appropriately. This report, therefore, re-estimated costs and effects using a standard approach for all interventions, although each study that could be found was evaluated to determine if the parameters it used could be incorporated. CHOOSING INTERVENTIONS TO REDUCE SPECIFIC RISKS The results reported in this chapter are important inputs to two types of policy ques￾tions. The first is how best to reduce the health burden associated with a specific risk factor, where information on the effectiveness and costs of the alternative interventions is one crucial input. The second is how best to reduce the health burden associated with risk factors in general, where information on the effectiveness and costs of interventions aimed as a variety of risk factors is critical. This section covers the first question, by reviewing the cost-effectiveness of selected interventions aimed at some of the main risk factors described

Some Strategies to Reduce Risk in Chapter 4. The same organizing format followed in that chapter is followed here. The question of how to decide what combination of those risk factors should be given priority for any given level of resource availability is considered on page 139 CHILDHOOD UNDERNUTRITION The strategy of primary health care was adopted by the World Health Assembly in 1977 and outlined further in the 1978 Declaration of Alma-Ata on Health for All ( 24). The dec laration encouraged governments to strive toward attaining Health for All by ensuring, at a minimum, the following activities: education concerning prevailing health problems, their prevention and control; promotion of food supply and good nutrition; safe water and basic sanitation; maternal and child health care which included family planning immunization against major infectious diseases; prevention and treatment of locally endemic diseases; appropriate treatment of common diseases and injuries; and provision of essential drugs Primary health care emphasized programmatic areas rather than diseases, and encouraged community and individual self-reliance and participation, an emphasis on prevention, and a multisectoral approach. Subsequently, the concept of"selective primary health care"was proposed to allow for the scarcity of resources available to achieve health for all. It involved defining strategies focusing on priority health problems(including infant and child mortality), using interven- tions that were feasible toimplement, of low cost, and with proven efficacy(25, 26). UNICEF's GOBI strategy of 1982 emerged from this. At its foundation were four child health inter- ventions which met the above criteria and which were considered to be synergistic-growth monitoring(G), oral rehydration therapy for diarrhoea(O), the promotion of breastfeeding (B)and childhood immunizations( D). Birth spacing/family planning(F), food supplemen tation(F)and the promotion of female literacy(F)were added subsequently( GOBl-FFF) There has been subsequent analysis and discussion of the extent to which the specific interventions can be integrated into primary health care, and whether strategies should be nodified in view of new knowledge and changing circumstances. However, concern with ensuring that child health strategies are based on feasible and affordable interventions that are synergistic and of proven effectiveness -has remained. This chapter builds on that tradition by providing information on the costs and effects of selected interventions target ing key risk factors affecting the health of children. The results not only identify a group of interventions that are very cost-effective, but also illustrate how information on the costs and effectiveness of selected interventions can provide useful insights that can be used to re-assess, from time to time, the need to modify current approaches in view of changing The focus is on interventions aimed primarily at the risk factors identified in Chapter 4 rather than all possible child health interventions. We have selected some interventions that can be delivered on a population-wide basis and some that focus on individuals, to illustrate how the two approaches interact. Childhood immunizations have not been in- cluded because they do not respond to one of the major risk factors of Chapter 4, and because it is already widely accepted that they are cost-effective(28).The fact that interven- tions are not included here, therefore, should not be taken to imply that they are not cost ettective

Some Strategies to Reduce Risk 109 in Chapter 4. The same organizing format followed in that chapter is followed here. The question of how to decide what combination of those risk factors should be given priority for any given level of resource availability is considered on page 139. CHILDHOOD UNDERNUTRITION The strategy of primary health care was adopted by the World Health Assembly in 1977 and outlined further in the 1978 Declaration of Alma-Ata on Health for All (24). The Dec￾laration encouraged governments to strive toward attaining Health for All by ensuring, at a minimum, the following activities: education concerning prevailing health problems, their prevention and control; promotion of food supply and good nutrition; safe water and basic sanitation; maternal and child health care which included family planning; immunization against major infectious diseases; prevention and treatment of locally endemic diseases; appropriate treatment of common diseases and injuries; and provision of essential drugs. Primary health care emphasized programmatic areas rather than diseases, and encouraged community and individual self-reliance and participation, an emphasis on prevention, and a multisectoral approach. Subsequently, the concept of “selective primary health care” was proposed to allow for the scarcity of resources available to achieve health for all. It involved defining strategies focusing on priority health problems (including infant and child mortality), using interven￾tions that were feasible to implement, of low cost, and with proven efficacy (25, 26). UNICEF’s GOBI strategy of 1982 emerged from this. At its foundation were four child health inter￾ventions which met the above criteria and which were considered to be synergistic – growth monitoring (G), oral rehydration therapy for diarrhoea (O), the promotion of breastfeeding (B) and childhood immunizations (I). Birth spacing/family planning (F), food supplemen￾tation (F) and the promotion of female literacy (F) were added subsequently (GOBI-FFF) (27). There has been subsequent analysis and discussion of the extent to which the specific interventions can be integrated into primary health care, and whether strategies should be modified in view of new knowledge and changing circumstances. However, concern with ensuring that child health strategies are based on feasible and affordable interventions – that are synergistic and of proven effectiveness – has remained. This chapter builds on that tradition by providing information on the costs and effects of selected interventions target￾ing key risk factors affecting the health of children. The results not only identify a group of interventions that are very cost-effective, but also illustrate how information on the costs and effectiveness of selected interventions can provide useful insights that can be used to re-assess, from time to time, the need to modify current approaches in view of changing knowledge and circumstances. The focus is on interventions aimed primarily at the risk factors identified in Chapter 4 rather than all possible child health interventions. We have selected some interventions that can be delivered on a population-wide basis and some that focus on individuals, to illustrate how the two approaches interact. Childhood immunizations have not been in￾cluded because they do not respond to one of the major risk factors of Chapter 4, and because it is already widely accepted that they are cost-effective (28). The fact that interven￾tions are not included here, therefore, should not be taken to imply that they are not cost￾effective