Intro
In an era when most societies must cope with increasing demand for health resources, they will inevitably have to make choices about the provision of health services, even if those choices are, by default, to continue current practices. Strategic health planning can accelerate health development and the attainment of health goals or reduce the cost of reaching such goals. Such planning must take into account the needs that the health system must address; that is, policy makers must be aware of the comparative burden of diseases and injuries and the risk factors that cause them, and how this burden is likely to change with the adoption of various policies and interventions. Needs are, of course, not the only factors determining service provision, but should be a critical component of the decision-making and planning processes.
The issue then becomes how to assess the comparative importance of risks to health and their outcomes in different demographic groups of the population. What is needed is a framework for integrating, validating, analyzing, and disseminating the fragmentary, and at times contradictory, information that is available on a population's health, along with some understanding of how that population's health is changing, so that the information is more relevant for health policy and planning purposes. The Global Burden of Disease (GBD) framework is the principal, if not the only, attempt to do so. Features of the GBD framework include the incorporation of data on nonfatal health outcomes into summary measures of population health, the development of methods for assessing the reliability of data and imputing missing data, and the use of a common metric to summarize the disease burden from diagnostic categories of the International Classification of Diseases and the major risk factors that cause those health outcomes.
Figure 1.1
presents a simplified version of this framework and indicates the causal chain of events that matter for health outcomes, identifying the key components and determinants of health status that require quantification.
[Figure
1.1]
Many countries and health development agencies have adopted the GBD approach as the standard for health accounting and for guiding the determination of health research priorities, for example, Australia ( Mathers, Vos, and Stevenson 1999 ); the state of Andra Pradesh, India ( Mahapatra 2002 ); Mauritius ( Vos and others 1995 ); Mexico ( Lozano and others 1995 ); South Africa ( Bradshaw and others 2003 ); Thailand ( Bundhamcharoen and others 2002 ); Turkey ( Baskent University 2005 ); the United States ( McKenna and others 2005 ); and the World Health Organization ( WHO 1996 ).
This chapter begins with a brief history of the work on burden of disease, including a discussion of the nature and origins of the disability-adjusted life year (DALY) as a measure of disease burden. Next it discusses applications of burden of disease analysis to the formulation of health policy. The chapter then summarizes the methods and findings of the 2001 GBD study, reported in more detail in chapters 3 and 4 of this volume. A concluding section takes stock of the work on disease burden since the early 1990s and suggests some key areas for further work.
Following this introductory and summarizing chapter, chapter 2 describes the demographic underpinnings for the epidemiological assessments that follow and provides context by briefly reviewing recent changes (from 1990 to 2001) in key demographic parameters. The chapter also assesses changes in the cause distribution of mortality among children under five between 1990 and 2001 and the difficulties of reliably assessing trends in mortality. Chapters 3 and 4 provide the definitive methods and results of the 2001 GBD study. Chapter 3 reports on deaths and the disease and injury burden by age, sex, and 136 disease and injury categories. Chapter 4 reports on the disease and injury burden resulting from 19 risk factors, specifically for a number of important conditions. Both chapters present results using the World Bank's classification of low- and middle-income countries into six regional groups. Chapter 5 then explores the robustness of the major findings to uncertainties in the data and to alternative assumptions concerning construction of the DALY. Chapter 6 examines the implications of including stillbirths in a global burden of disease assessment. Their inclusion is potentially significant, both because the numbers are large (3.3 million in 2001), and because including stillbirths raises major questions about how to assess the DALY loss associated with deaths near the time of birth.
