The Burden of Disease research team aims to provide comparable estimates of the impact of diseases and injuries in all countries to inform priorities for policies, funding, and further research. Individual indicators about health conditions – such as the total number of deaths by age and sex, or the incidence of particular conditions – are useful but insufficient to understand the real impact of a given condition on a population.
To assess the burden of disease, both mortality and morbidity must be taken into account using the disability-adjusted life year (DALY). The DALY is a time-based measure that combines years of life lost due to premature mortality and years of life lost due to time lived in health states of less than ideal health.
Several research activities conducted by this team feed into the
Global Burden of Diseases, Injuries, and Risk Factors 2010 Study (GBD 2010 Study). This study is a complete systematic assessment of the data on all diseases and injuries, producing comprehensive and comparable estimates in DALYs for 1990, 2005, and 2010 for 21 individually distinct but globally comprehensive geographic regions. IHME is the lead institution for the GBD 2010 Study, with collaborators from Harvard University, Johns Hopkins University, the University of Queensland, the World Health Organization, and 800 condition-specific experts from around the world.
Other IHME research teams involved in the GBD Study include Causes of Death, Demographics: Mortality and Population, Risk Factors, and Functional Health Status. By approaching each condition in the same way and analyzing all available data, this effort will produce the most highly comparable and methodologically advanced set of burden estimates available, so that decision-makers have the evidence they need to design the best prevention and treatment programs.
While IHME is coordinating the regional estimates for the collaborative study, the Burden of Disease research team is concurrently working on methods to generate country-level burden estimates by age and sex as part of IHME’s core work in the Measuring Health research area.
Other key activities for the Burden of Disease research team include data collection and the generation of incidence and prevalence estimates for key conditions.
Key Activities
- Finalize the development of DisMod III, a tool for producing estimates of incidence and prevalence
We often need to estimate average duration from known rates of remission or death for a particular condition. To do this, the research team has developed DisMod III, a computer software program that allows the user to check if a set of assumptions on incidence, prevalence, remission, case-fatality rates, and observed mortality rates are consistent with one another. DisMod III then allows users to calibrate the number and size of age groups for input and output variables as required, supplement available data with expert knowledge, and force the estimates to be internally consistent. This disease modeling tool can be useful for a range of conditions, population considerations, and time periods.
The research team aims to refine the tool in a manner that can be used more fully by a wider range of researchers.
- Produce a new analytic engine to calculate DALYs
The DALYnator combines estimates from the Cause of Death Ensemble model (CODEm), which produces years of life lost, and DisMod, which produces years lived with disability, with health state severity weights to produce estimates of disease burden in DALYs with an appropriate degree of uncertainty.
The DALYnator tracks the uncertainty intervals around all of these measurements, ensuring that the resulting outputs accurately reflect the confidence of the predictions. The DALYnator also considers complications that arise in calculating health state severity measures for conditions that are often comorbid.
- Produce burden estimates for all conditions and risk factors
This key activity by the Burden of Disease research team directly supports the ultimate goal of the GBD 2010 Study, to produce estimates of disease burden for 220 conditions and approximately 40 risk factors by age and sex in 21 regions of the world for 1990, 2005, and 2010.
- Refine methods to assess incidence and prevalence of key conditions in populations
Population-level incidence and prevalence of chronic conditions are often poorly understood because of a lack of data. A validated population-based survey providing accurate information on such conditions could be a cost-effective way to fill significant data gaps. As part of the
Population Health Metrics Research Consortium Mexico Study, the research team has fielded a survey instrument in Mexico City.
To validate the instrument, the study ties the surveys back to verified clinical information about individuals interviewed about conditions of interest, including angina pectoris, chronic obstructive pulmonary disease, asthma, depression, vision loss, hearing loss, cirrhosis of the liver, osteoarthritis, rheumatoid arthritis, and cataracts.
Drawing from the lessons learned through the analysis of verbal autopsies, the research team is developing a new method, the Symptom Diagnosis Method, to analyze the collected data.
- Produce an in-depth assessment of the incidence and mortality of breast and cervical cancer globally
With support from Susan G. Komen for the Cure, the research team has generated country-level estimates of breast and cervical cancer incidence and mortality from 1990 to 2010 for 187 countries. This work has led to both a peer-reviewed
journal article and a
policy report.
Impact
Improving the health and well-being of the world’s population is a moral imperative and is essential for global stability and progress. The vast energies, technologies, and resources pouring into global health have given us the capacity to reduce disease, improve health conditions, and address deep inequalities in health between populations.
The Burden of Disease research team provides tools and knowledge to inform efforts for making effective interventions possible.
