From health risks to policy
Earlier 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 exposure 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 considered in the analysis detailed in this chapter. Some interventions have been widely implemented 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 population 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 several attempts to standardize methods to make results comparable (1,3). WHO has developed 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.
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 interventions 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 burden 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 relation 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 settings. 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 improvements 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 consider 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 incorporate 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 stewards of their health systems(5). If the population uses interventions that are ineffective, dangerous, or are simply not good value for money, 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.