In the global burden of disease (GBD) project, the disability-adjusted life year (DALY) is used as a measure of disease burden. DALYs combine years of life lost to premature death and years lived with a disability or condition, weighted for the severity of the condition. This combined measure makes it possible to compare conditions with different symptoms and outcomes using a standardized metric. Initiated in the early 1990s, the methods used to measure the GBD recently underwent major revision. Details about the new methods and up-to-date information about the state of in the world were published in the December 2012 issue of the Lancet, which was devoted entirely to the GBD 2010 study. (1) Although the new methods used to calculate the GBD are a considerable improvement over previous ones, central concerns about the utility of DALYs for making decisions about the prioritization of conditions and the allocation of resources remain unaddressed. General concerns and how they were addressed Since their inception, GBD studies have been criticized for their methodological and normative choices in four areas: the use of age weighting (i.e. the assignment of different weights to years of life lost at different ages); the use of different life expectancies for men and women; discounting (i.e. the assignment of a lower weight to years of life lost in the future); and the determination of disability weights, which are intended to capture the severity of a condition. The team that conducted the GBD 2010 study took these criticisms seriously and enlisted experts in multiple disciplines to help revise its methods. In response to the first three criticisms it dropped discounting, made age weights uniform and used the same life expectancy for men and women (86 years) to calculate years of life lost. (1) To address the fourth criticism, the team revised its method for determining disability weights. These are standardized values that are assigned to non-fatal outcomes to capture their severity on a scale between 0 (full health) and 1 (death). For example, in the GBD 2010 study, complete hearing loss and severe chronic neck pain were assigned disability weights of 0.033 and 0.286, respectively. Many critics of earlier GBD studies, which were originally commissioned in 1990 and have been updated twice since, were dissatisfied with the particular person trade-off method used to determine disability weights. The method consisted of asking respondents to choose between different hypothetical public interventions. (2) Subsequently, critics questioned the feasibility of developing a standardized measure. They argued, furthermore, that the disability weights incorporated into the DALY, which were originally elicited from a small group of highly educated experts, could not be generalized to respondents from different geographic, cultural or socioeconomic backgrounds. Many doubted that a single universal measure of could be validly applied to all settings, given marked differences among countries in baseline levels of and socioeconomic development. Finally, some critics contended that health cannot--or should not--be separated from general welfare, which is shaped not only by an individual's symptoms but also by the interaction of those symptoms with the environment. The GBD 2010 study team formulated several responses to these concerns. First, the GBD 2010 study surveys employed brief lay descriptions of the symptoms and functional consequences of various states in an attempt to isolate losses in from losses in welfare and from the impact of the social environment. (3) This method reflected the assumption that the GBD study should capture health in a narrow sense. The insistence on a narrow understanding of stemmed from the conviction that, even though the experience of a particular condition (e. …
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