DALY (Disability Adjusted Life Years)
1. Description
DALY (Disability Adjusted Life Years) is an index quantifying number of years lost from treatment compared to the national life expectancy.[1] It weighs the individual level of disability and counts both the year of loss due to disability and the year short of the local/national life expectancy. DALY can also act as a population measure by summing up DALYs for each individual in the population.
2. Evaluation
2.1 Principle
- DALYs provide a common currency for both benefit and risk (in terms of life lived and lost) adjusted for "disability".
- DALYs are meant to complement QALYs.
- DALYs can be combined with QALYs using the benefit-risk ratio (BRR) approach to estimate benefit-risk balance.
- The principles are however flawed, without a fixed reference population.
2.2 Features
- Benefit and risk are integrated, and so is the time dimension.
- DALY accommodates multiple criteria.
- A sensitivity analysis can be performed on various parameters in DALYs e.g. different reference population or data.
2.3 Visualisation
- Visualisations similar to the one used for QALYs may be used.
2.4 Assessability and accessibility
- The use of the local/national life expectancy to determine the years of life lost is problematic.
- DALY is otherwise only semantically different from QALY if the reference population issue is solved.
