Incorporating quality of life changes into economic evaluations of health care: an overview.

The demand for economic evaluations of health care programs, especially pharmaceuticals, is steadily increasing. One of the most important issues in this field is how to measure, value and incorporate changes in quality of life into the economic evaluation. We provide an overview of the different approaches to measure changes in quality of life: quality of life instruments, the quality-adjusted life-year (QALY) approach and the willingness to pay approach. Quality of life instruments have major practical advantages since they are easy to administer. The results of these instruments cannot, however, be used in economic evaluations. In economic evaluations, the quality of life has to be measured on the 0 (death) to 1 (full health) scale necessary to construct QALYs, or the willingness to pay for the changes in quality of life has to be measured. Such measurements are, however, much less straightforward to carry out. It would therefore be a major advance if it would be possible to directly translate the quality of life score into a QALY weight or the willingness to pay. It is recommended that more systematic research should be carried out on the relationship between quality of life, QALY weights, and willingness to pay.