Functional Health Status

The health of a population cannot be measured solely by mortality rates and causes of death. The ability to function for those who may have become sick or disabled through disease or injury is also an important measure of population health. For example, back pain or the loss of a limb may detract from one’s overall health and should also be taken into account.

IHME’s Functional Health Status research team works to assign “weights” to various health states so that estimates can be made about the overall scale of disability. The information we are generating is essential for policymakers, public health officials, and others to understand the disease burden in their communities. IHME is currently conducting a comprehensive disability weights study as part of the newest round of the Global Burden of Disease Study 2010, aiming to calculate the years lived with disability and ultimately produce the most accurate measurement to date of the disability-adjusted life year, or DALY. The DALY is an important measure in health care accountability because it allows measurement of not only loss of life but also reduction in function.

Another critical component in obtaining an accurate picture of disease and injury impacts is the development of standardized measurements of functional health states so that meaningful comparisons can be made over time and across populations. IHME is working on the development of methods to enhance comparable measurement.

Major activities in Functional Health Status:

Finalize list of disabling sequelae for the GBD Study 2010:

For each of the identified diseases, injuries, and risk factors being examined as part of the GBD Study 2010, a set of sequelae needs to be identified that cause detriments to health. A sequela might be chronic back pain, which itself could be the result of myriad causes. The aim is to define a list of sequelae mapped with precision to the various causes. A disability weight is then assigned to each sequela in turn. This task began in 2009 with a central group of researchers in consultation with the GBD Study’s condition-specific experts, with the goal of producing a single consistent list for use in this and future GBD sets of estimates.

Collect and analyze disability weights measurement data from field sites and Web surveys:

A key criticism of the original GBD Study was that it relied largely upon expert opinion, rather than population surveys, to judge the relative detriment to health that different sequelae posed. To counter that criticism, researchers involved with the current study have conducted household surveys in several diverse sites – Bangladesh, Peru, Tanzania, Indonesia, South Africa, and the United States. The surveys ask respondents to judge the relative severity of states of health in a series of paired comparisons and time trade-off questions. These data will be augmented by an online survey targeting a larger audience in spring 2010. All data will be analyzed and used as an input into the overall GBD Study.

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