The concept of a ‘health status index’ was first developed in the 1970s with the formulation of the Quality-Adjusted Life Year, and was created as a tool to measure health outcomes. Health status index formulas are derived from data on both the duration and quality of life for an individual.
The DALY was first introduced as an independent measurement in 1993 in the World Bank’s World Development Report (Fox-Rushby & Hanson, 2001). Perhaps its most popular use, the DALY is the central measure used in the “Global Burden of Disease” research series and is used in conducting CEAs in developing countries (Fox-Rushby & Hanson, 2001). Research on cost-per-DALY literature has lagged far behind that of cost-per-QALY literature, indicating a need for systematically characterizing and cataloging cost-per-DALY studies.
The DALY is a popular measurement in prioritizing health resource allocation, especially in developing countries. Limited resources in these countries require careful consideration of healthcare spending, grounded in evidence-based prioritization through the use of the DALY metric. The World Health Organization (WHO) recommends the DALY as an effectiveness indicator to “facilitate the smooth transition from cost-effectiveness analysis to social cost-benefit analysis through the valuation of time” (Edwards, 2011). It is generally considered to be an extremely efficacious tool in comparing disease burden on an international scale, and is used for prioritizing resource allocation in a variety of well-respected international organizations.
Popular Usage and Examples
Prominent organizations such as the World Health Organization (WHO) and the Bill and Melinda Gates Foundation use the DALY to prioritize monetary allocations for global health interventions
World Health Organization (WHO): The WHO’s Global Health Observatory defines the DALY as the “summary measure used to give an indication of overall burden of disease,” and as the best metric by which to study the burden of diseases. WHO-CHOICE, the WHO’s program for cost-effectiveness and strategic planning, looks at interventions in developing countries through an “average cost-per-DALY averted” metric. The WHO used the DALY in comparing 91 different treatments/treatment combinations for HIV in East Africa:
- Treatments were ranked on the DALYs averted per year, average cost-per-DALY averted, and incremental cost-per-DALY averted
- Mass-media education efforts, treatments for female sex workers, and treatment of STIs in the general population all cost <$Int150 per-DALY averted
- School-based education strategies and various antiretroviral treatment strategies cost between $Int500 and $Int5000 per-DALY averted
- Mass-media campaigns are the most cost-effective way to reduce HIV transmission
- Antiretroviral therapy is the least cost-effective method (Hogan, et al., 2005).
See more at: World Health Organization (WHO)
The Bill and Melinda Gates Foundation: Within the Global Health and Global Development sectors of the Gates Foundation, the “cost-per-DALY averted” metric is used as a tool for measuring the projected outcomes of invested funds. The Gates Foundation has identified efficient areas for investment within developing countries using this metric. For example:
- Promoting breastfeeding from birth until 6 months of age has a cost range of $2-$7 per DALY averted, and is considered a highly cost-effective measure
- Fortifying foods with zinc, iodine, and other key vitamins is extremely cost-effective (fewer than 25 cents annually per person, in some cases); $8-$30 per DALY saved.
See more at: The Bill and Melinda Gates Foundation
Edwards, C. (2011). 10: Cost-effectiveness analysis in practice. In J. Cameron, P. Hunter, P. Jagals & K. Pond (Eds.), Valuing water, valuing livelihoods (pp. 181-197). London: IWA.
Fox-Rushby, J. A., & Hanson, K. (2001). Calculating and presenting disability adjusted life years (DALYs) in cost-effectiveness analysis. Health Policy and Planning, 16(3), 326-331.
Gates, B. (2010). Bill gates: Testimony before the senate committee on foreign relations . Retrieved from http://www.gatesfoundation.org/Media-Center/Speeches/2010/03/2010-Senate-Testimony
Hogan, D. R., Baltussen, R., Hayashi, C., Lauer, J. A., & Salomon, J. A. (2005). Cost effectiveness analysis of strategies to combat HIV/AIDS in developing countries. BMJ, 331(7530), 1431-1437.