Uncertainty analysis of quality adjusted life years lost

Quality Adjusted Life Years (QALY) can be used to measure the impact of a public health problem on quality and quantity of life. Instruments that measure QALYs put preference on different health dimensions to reflect their value within society.  However, comparisons of these instruments have found varying estimates for the same illness. 

Our study was conducted using the Injury Impairment Index for future analysis of QALY losses due to injuries. However, the method that we will present can be applied to other areas of public health.

The III is a preference-based instrument that includes six health dimensions with four levels of severity within each dimension.  Uniquely, the preference weights used in the III are derived from a review of preference weights used in other instruments. The variability between these instruments is the basis for the sometimes wide range of preference weights incorporated into the III. 

We examined the variability in preference weights associated with the different health dimensions and levels within the III using updated values found in the more recent literature. The variability was analyzed and then applied in sensitivity analysis to examine the resulting range of QALY loss estimates for injury.

We will present and discuss the mapping of dimensions/levels from other instruments to the III.  We will present the range of instruments and preference weights for each III dimension/level found in the literature review.  We will present our findings of the “best” preference weight estimates and the corresponding uncertainty ranges for each III dimension/level. Finally, we will present the transformation of preference weights into QALY estimates.