Measuring the burden of injury

The political response to any given health problem is strongly influenced by two particular metrics: the scale of the problem and the effectiveness of acceptable counter measures. Injury prevention advocates need information on the comprehensive burden of injuries to be able to effectively argue for greater investment in interventions that have been shown to be cost-effective. Where high-grade evidence is lacking, investment in research is also needed to develop and test the effectiveness and cost-effectiveness of new interventions and strategies. Thus, accurate and comprehensive measurement of the burden of injury is an essential component of injury prevention.

The “burden of disease” concept was introduced by the World Health Organization in 1996 in the Global Burden of Disease (GBD) Study.1 This approach involved combining measurement of disability in those surviving an injury with excess mortality after injury. Disability-adjusted life years (DALYs) lost consequent to illness or injury was the metric chosen to measure burden.2 There are two classes of DALYs: years of life lost due to premature mortality (YLLs), and years lived with disability adjusted for the severity of disability (YLDs). The creation of YLLs and YLDs involved quite complex steps, including determining or calculating a number of parameters: the duration of life lost due to a death at each age; age weighting, a process by which lives at different ages are given different values; discounting, an economic concept that reflects individual and societal preferences for present rather than future benefits; and comparing time lost due to premature death and time …