Summary
The Challenge of Diseases Dean Jamison Kennedy School of Government and School of Public Health, Harvard University
This paper was produced for the Copenhagen Consensus 2008 project. The final version of this paper can be found in the book, ‘Global Crises, Global Solutions: Second Edition’, edited by Bjørn Lomborg (Cambridge University Press, 2009)
copenhagen consensus 2008 diseases executive summary
Disease Control Dean T. Jamison, Prabhat Jha and David Bloom This paper updates the evidence and comes to somewhat different conclusions from the communicable diseases paper prepared for the 2004 Copenhagen Consensus. It builds on the results of the Disease Control Priorities (DCP) Project, under which over 350 authors estimated the cost-effectiveness of 315 interventions. Progress and challenges The second half of the 20th century saw great improvements in health conditions across much of the world, but there are still major problems at the beginning of the 21st. Some regions have simply failed to make much progress, declines in mortality and fertility make non-communicable diseases more important, and HIV/AIDS presents major new problems.
Progress
Life expectancy has increased markedly in low- and middle-income countries, but progress in recent years has become slower and longevity has actually decreased in subSaharan Africa since 1990. Although on average life expectancies are converging towards an ever-increasing maximum, there remain large differences between and within countries. Much of the difference between countries results from variations in the penetration of appropriate health technologies. In some countries, technical progress is reducing infant mortality by up to 5% annually, while in others it makes no contribution at all. There has been a remarkable decline in infectious disease (with the exception of HIV). In 1970, perhaps only 5% of the world's children were immunized against measles, tetanus, pertussis, diphtheria and polio. By 1990, this had increased to about 75% of children, saving maybe 3 million lives each year, and smallpox has been totally eradicated. A wide range of antibiotics and other antimicrobials now make it possible to treat many diseases effectively. Fatality rates from tuberculosis have been reduced from well over 60% to 5%, and transmission has decreased. Research into HIV/AIDS and other viruses is accelerating the development of anti-virals, and advances in molecular biology and recombinant DNA technology give enormous promise for the future. Education also plays a significant role in health improvement, but increasing prosperity much less so. It seems that it is healthcare policy rather than income which is the key factor in determining outcomes. There is clear evidence that dramatic improvements in health can occur without high or rapidly-growing incomes.
Remaining challenges
Unequal progress Although global health inequalities are declining, there are too many countries where conditions are unnecessarily poor. Apart from causing human misery, this is a barrier to poverty reduction. 23 countries made no progress or had further increases in infant mortality between 1990 and 2001; in 53 others the rate of decline is less than half the 4.3% necessary to meet the Millennium Development Goal (MDG) for under-five
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mortality. But dramatic improvements have been made in many other countries, which are often quite poor. Epidemiological transition A combination of aging populations and lifestyle changes (including smoking) are making the major non-communicable diseases – cardio-vascular disease, cancers, respiratory disease and major psychiatric disorders – an ever-increasing part of the total morbidity load. In addition, injuries in road accidents are replacing other forms of injury. This creates an additional burden on very constrained resources. HIV/AIDS epidemic The third key challenge is HIV/AIDS, best viewed as a set of diverse epidemics in regions and sub-regions. Although there has been little improvement in parts of Eastern and Southern Africa, prevention programs in large parts of Asia, Latin America and elsewhere may be contributing to a slowing in the spread of infection. The economic benefits of better health The dramatic improvements in health during the 20th century arguably contributed as much to well-being as the equally dramatic growth in material goods and services. Welltargeted investments in health can continue to reduce levels of morbidity and mortality, and returns on investment are likely to very high.
Health and income
Healthy workers are more productive, as is shown by positive links between investment in health and nutrition and adult wages. Incomes are also boosted in other ways. For example, increased life expectancy means that people for the first time begin to make provision for retirement, and the savings boom can substantially increase investment and economic growth. Foreign direct investment is also encouraged if the workforce is healthier and more productive, access to natural resources can be greatly improved as endemic diseases are controlled, and healthier children are more likely to attend school. Demographics also change as reductions in infant mortality lead to a baby boom, followed by a reduction in family size. The baby boom generation provides a large labor force which can drive economic growth. All these factors lead to higher levels of national income in the long run. Studies show, for example, that 10-15% of economic growth can be accounted for by increased longevity, and one extra year of life expectancy can raise GDP per capita by 4%. Declines in health, for example via HIV/AIDS epidemics, can on the other hand lead to a downward economic spiral.
Health and economic welfare
GDP per capita fails to capture the full picture of economic performance; at a given income level, the enjoyment of longer and healthier lives represents a clear additional benefit. The value of life expectancy increases may be quantified as the value of a statistical life (VSL), which can be added to GDP to provide a measure termed full income. This measure is conservative, since it takes no account of changes in health status. A more complete measure is the disability adjusted life year (DALY), which takes account of morbidity as well.
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Indications are that rapid increases in life expectancy can be the major contributor to rising full income in poor countries, and that overall inequality declines, even though income inequality may increase. Studies by the WHO and IMF have also shown that the impact of the AIDS epidemic on full income is much greater than on GDP alone. Use of full income rather than GDP as a measure of economic welfare would probably conclude that investment in health should deserve a higher priority. Cost-benefit methodology
Cost-effectiveness analysis broadly and narrowly construed
In broad terms, health systems try to both improve health outcomes and protect individuals from financial risks (both loss of income and costs of care). There are two classes of resource available: financial and capacity of the health system. While some interventions have high costs, others may be more demanding of capacity, particularly human resource. This becomes an important criterion for prioritizing interventions. While there may be little trade-off between cost aspects and capacity factors in the short term, investment in resources can make delivery more effective in the longer term. More narrowly, cost effectiveness can be expressed as the cost of averting a DALY. However, when making prioritization decisions, the consequences for financial protection and demands on health system capacity must be borne in mind.
The value and cost of a DALY
Using VSL estimates, we can assign a value for a statistical life year in the range 2-4 times per capita income. Using World Bank estimates of average incomes in poor countries, we arrive at a DALY value of $1,000 as a conservative figure for use in further analysis. The cost of buying a DALY is based on typical regional costs rather than purchasing power parity rates, since this would be the basis used by local decision makers. We explore the sensitivity of our results to these assumptions by using a DALY value of $5000. Child health A small number of conditions account for most of the large differences in health between the poor and the more prosperous. Less than 1% of deaths from AIDS, TB and malaria occur in high-income countries, for example. Immunization and other relatively low-cost options can address most of the conditions which affect children.
Under-5 health problems and intervention priorities
Although the MDG for under-five mortality (a reduction by two-thirds from 1990 to 2015) is highly ambitious, in the period to 2002 46 countries had achieved higher annual rates of decline than the 4.3% needed to meet the goal. Three important points emerged from the latest DCP report. First, declines in mortality could be accelerated with expanded case management of acutely-ill children and expanded routine vaccinations. Hib (Haemophilus influenza type b), pneumococcal, rotovirus and shigella vaccines together could save 1.4 million lives annually by 2010. Second, half of all under-five deaths are at less than 28 days, if stillbirth is included, and cost-effective interventions against this and neonatal death are available. Third, as malaria becomes increasingly resistant to standard inexpensive drugs, it is important to be able to finance a move to artemisinin combination therapies (ACTs).
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These are in addition to other familiar interventions, including exclusive early breastfeeding, expanded immunization coverage, greater use of low cost, highly effective treatments for diarrhea and childhood pneumonia, use of insecticidal bednets and other interventions against malaria, ensuring widespread distribution of key micronutrients and expanding the use of anti-retrovirals and breast feeding substitutes to prevent mother-tochild transmission of HIV. A further problem affecting children of all ages is infection with intestinal helminthes (worms), the most prevalent infection of all. A low-cost drug (albendazole) can provide effective control, but the long-term solution lies in improved sanitation and water supplies.
Delivering child health interventions
One view is that it is sufficient to provide more money and focused effort to provide the range of interventions identified, with additional funding able to build capacity over a relatively short period. The alternative school of thought is that, although more money is needed, system reform is critical if capacity is not to be the limiting factor. We tend to the former view, while acknowledging the need to be explicit about nonfinancial costs. Attention needs to be given to how constraints can be relaxed, and interventions chosen which are less demanding of non-financial resources. Experience with immunization in Malawi, one of the world's poorest countries, suggests that this approach can be effective. HIV/AIDS and tuberculosis AIDS represents the single biggest threat to development in dozens of low- and middleincome countries. National and international responses have been slow, although the Global Fund to fight AIDS, Tuberculosis and Malaria has achieved some real success, albeit now compromised by resource constraints. In contrast, the research community (both public and private) has made rapid progress in developing diagnostic and control tools, which countries including Thailand, Brazil and Mexico have used to forestall potential epidemics.
Prevention of HIV transmission
HIV has reached every country in the world, but patterns of infection vary. In east and southern Africa, it has spread rapidly throughout the population, with infection rates of 15% in South Africa and 30% in Botswana in 2005, for example. A few other African countries have shown substantial increases, with rates now above 3%, while the rest of Africa and almost every other country in the world has a prevalence rate below 3%. Although factors such as male circumcision are known to be important, the reasons for these different patterns are not well understood. Prevention of HIV transmission is a key challenge, and interventions among sex workers and other vulnerable groups in order to minimize risks can be highly effective. A few Asian countries – with Thailand being the best-known example – have acted early to target vulnerable groups and keep infection rates low. Treatment for sexually transmitted diseases (STIs) can help with HIV control, and mother-to-baby transmission can be drastically reduced by giving the mother a short course of anti-retrovirals and encouraging breast milk substitutes. Needle exchanges and blood safety programs can 4
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reduce these less common forms of transmission. Overall, national leadership and avoiding stigmatization of vulnerable groups increases program effectiveness. In those sub-Saharan African countries with generalized epidemics, a national approach is vital. HIV prevalence in Uganda had declined from 20% to 10% from 1990 to 1999, but the reasons are not clear, and the experience has not yet been replicated elsewhere.
Antiretroviral treatment of AIDS
Although preventing further spread is vital, the 40 million current sufferers (95% in lowand middle-income countries) cannot be neglected. Highly active anti-retroviral therapy (HAART) has dramatically reduced AIDS mortality in developed countries, but the drugs must be taken for life. With improved, lower cost drugs now available, lower-income countries can be targeted. WHO's "3 by 5" program had an objective of reaching 3 million people in low- and middle-income countries with these drugs by 2005, although reality fell well short of the target. A significant problem in low-income countries remains the need for sufficient human resources to cope with the complexities of patient management. Another issue is that poor implementation would lead to very limited health gains while taking resources from other areas. Learning from experience what works best is key to success. Part of this is to end the reliance on the cheapest possible drugs. Although use of anti-retrovirals is likely to be cost-effective in many cases, it will compete with other highly attractive investments.
Control of tuberculosis
TB is the second largest cause of adult deaths after HIV/AIDS. There were nearly 9 million new cases and perhaps 1.6 million deaths in 2003. 90% of cases are in low- and middle-income countries and poverty, household crowding and smoking are key risk factors. The principal treatment strategy is known as DOTS: diagnosis and treatment of the most severe form of the disease but including treatment of less severe and latent forms. The widely-used BCG vaccine prevents the disease in childhood. There is an MDG for reducing the incidence of tuberculosis, and the Stop TB Partnerships calls for a halving of prevalence and deaths between 1990 and 2015. These goals can be achieved if 70% of serious cases are detected and 8% of these successfully treated with the DOTS regime. Progress has been good, with detection rates at 53% in 2004. Key challenges remain the spread of HIV in Africa and drug resistance, particularly in Eastern Europe. Evaluation of the WHO DOTS strategy (valuing life at a high 100 times GDP per capita) gives a net gain of $1.7 trillion for a cost of $18.3 billion in the 22 high burden countries. For the global DOTS program, the benefit-cost ratio is 15 in these countries and 9 in Africa. Non-communicable disease Developing countries not only need to address health problems which are effectively controlled in the industrialized world, but now also have to cope with an increasing incidence of conditions such as CVD and cancer.
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Cardiovascular disease
CVD in low- and middle-income countries results in about 13 million deaths each year, a quarter of all deaths in these countries and more than twice the number caused by AIDS, malaria and TB combined. As in high-income countries, these deaths occur later in life than infectious diseases and therefore form a substantially smaller proportion of the total disease burden in DALYs; just 12.9%. However, a far larger proportion of these deaths occur in middle age (30-69) than is the case in richer countries, where they predominantly affect older people. The key risk factors are high blood pressure, high intakes of saturated fat, smoking, obesity, binge drinking, physical inactivity and low fruit and vegetable consumption, and together these account for very large fractions of total deaths from CVD. However, with a few exceptions, efforts to change behavior have had little success at the population level. Highly cost-effective drugs to manage hypertension and high cholesterol in individuals at high risk of a stroke or heart attack are well established. Aspirin can provide further benefits. Risks can be reduced by 50% or more, but the necessary personnel and systems capability to provide and manage such lifelong medication remain a problem in many countries. Provision of inexpensive drugs to treat acute heart attack, on the other hand, is less demanding on resources, but the system must still be able to provide these drugs at the right time.
Tobacco addiction
Smoking is a significant cause of death in middle age in most low-income countries, although the actual disease pattern varies between countries. In 2001, over 3.3 million deaths (9% of total deaths over 5) in developing countries were tobacco related, and tobacco use is on the increase. Preventing people from starting to smoke is important, because addiction makes cessation difficult. However, helping people quit is at least as important. Public policy can be very effective in this regard, as shown by experience in many OECD countries. 30% of the adult population in the OECD are ex-smokers, compared to 2% in India and 9% in China. Increased tobacco tax can be particularly effective in reducing the level of smoking, especially among the poor (a 10% increase can lead to a 4-8% reduction in smoking). Publicity about health risks also helps, as recent experience in China shows. Tobacco use is different from other health challenges in that it involves use of a consumer product with presumed benefits to the user. Accounting for the loss of benefit, and also for addiction, can be difficult, but the health costs to smokers are huge. Opportunities for disease control For each proposed intervention, there is a broad range of benefit-cost ratios, depending on the exact assumptions, so there is little point in providing precise estimates with our recommendations. Instead, we have used conservative assumptions (a DALY valuation of $1,000 and a reduction of 50% in the DALY value for an under-5 death) to identify seven major opportunities which address a large disease burden highly cost effectively and which have enormous benefit-cost ratios.
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The proposed interventions, with indicative benefit-cost ratios, are: 1. Tuberculosis: appropriate case finding and treatment (1 million adult deaths or 30 million DALYs averted; BCR 30:1) 2. Heart attacks (AMI): acute management with low-cost drugs (300,000 heart attack deaths averted – 7.5 million DALYs; BCR 25:1) 3. Malaria: prevention and ACT treatment package (500,000 deaths averted – 7.5 million DALYs; BCR 20:1) 4. Childhood diseases: expended immunization coverage (1 million child deaths averted – 20 million DALYs; BCR 20:1) 5. Cancer, heart disease, other: tobacco taxation (1 million adult deaths averted – 20 million DALYs; BCR 20:1) 6. HIV: prevention package (2 million HIV infections averted – 22 million DALYs; BCR 12:1) 7. Injury, difficult childbirth, other: surgical capacity at the district hospital (30 million "surgical" DALYs averted, about 20% of DALYs; BCR 10:1) Overall, TB treatment stands out as perhaps the most important investment because of its high BCR, high level of financial risk protection, moderate demands on the system and large disease burden potentially averted.
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