Health outcomes in economic evaluation: the QALY and utilities.

The quality-adjusted life year (QALY) is routinely used as a summary measure of health outcome for economic evaluation, which incorporates the impact on both the quantity and quality of life. Key studies relating to the QALY and utility measurement are the sources of data. Areas of agreement include the need for a standard measure of health outcome to enable comparisons across different disease areas and populations, and the methods used for valuing health states in utility measurement. Areas of controversy include the limitation of the QALY approach in terms of the health benefits it can capture, its blindness towards equity concerns, the underlying theoretical assumptions and the most appropriate generic preference-based measure of utility. There is growing debate relating to whether a QALY is the same regardless of who accrues it, and also the issue as to who should value health states. Research is required to further enhance the QALY approach to deal with challenges relating to equity-weighted utility maximization and testing the validity of underlying assumptions. Issues around choosing between condition-specific measures and generic instruments also merit further investigation.