The health of a population is determined by more than mortality rates and causes of death. The ability to function for those who may have become sick or disabled from disease or injury is a critical input to population health measurement. One of the advantages of using disability-adjusted life years (DALYs) to measure population health is that they take into account both mortality and morbidity.
In order to elevate morbidity to equal significance as mortality and define a metric that measures them comparably, we need to know the degree of health detriment that should be attributed to any morbid condition. The information is essential for policymakers, public health officials, and others to understand the major causes of disease burden in their communities and design programs to reduce that burden.
The Functional Health Status research team works to assign severity weights to various health states, such as back pain or deafness, so that comparable estimates of the burden of disease for all major health conditions can be made. The “health state severity weights” generated by the Functional Health Status research team are critical for accurate assessment of a population’s health and for better targeting scarce resources. If policymakers were just to look at incidence and prevalence alongside of causes of death, they may underappreciate the significant impact that some types of nonfatal conditions, such as depression, have upon populations.
Key Activities
- Collect and analyze health measurement survey data
The research team is conducting a comprehensive health measurement survey to derive health state severity weights as part of the Global Burden of Diseases, Injuries, and Risk Factors Study 2010. The overall study aims to calculate the years lived with a disability and to produce the most accurate measurement to date of DALYs by age and sex for 21 regions for 1990 and 2010. To help set the severity weights for each nonfatal condition, the research team, with collaborators at the Harvard School of Public Health, developed a household survey that asked respondents to judge the relative severity of states of health in a series of paired comparisons and time trade-off questions. The survey was carried out in diverse settings, including Bangladesh, Peru, Tanzania, Indonesia, South Africa, and the United States. The survey has been adapted to the Web and translated into Spanish, targeting a larger global audience. The collected data is being analyzed and will lead to the development of the health state severity weights used in the GBD Study 2010.
- Refine functional health status instruments for use in surveys and clinical settings
Our knowledge about population- and individual-level functional health status could be greatly enhanced by combining information from a concise set of survey questions with some key indicators collected in clinical settings. Outside of specific research studies, there have not been extensive efforts to link and use this data in a time- and cost-efficient manner. If this could be done, it would provide much greater information about health care needs and effects. The research team is attempting to refine such approaches in work with the Dartmouth Institute for Health Policy & Clinical Practice and in the Monitoring Disparities in Chronic Conditions Study.
Impact
To our knowledge, the health measurement surveys on severity weights represent the first of their kind. Prior burden of disease studies have all relied upon expert opinion to determine severity weights, and using a population-based approach to gathering comparison data will lead to better, more accurate results. Furthermore, these survey-based results will help produce the most comprehensive and analytically-advanced set of burden of disease estimates generated to date. Equipping people with survey tools that can easily augment information from clinical settings would help empower policymakers to effectively target health care capacity.
