Cost-effectiveness of epilepsy therapy: how should treatment effects be measured?

Economic evaluations aim to inform policy makers about the cost-effectiveness of different therapies so that limited health care resources may be allocated efficiently. For such evaluations, the effects of therapy must be captured by measures that are reliable, valid, and clinically meaningful. Mortality and changes in disease activity (e.g., seizure freedom, reduction in seizure frequency) may be reliable and valid, but their clinical meaning is not always apparent. Changes in widely used "quality-of-life" measures can quantify therapeutic effects, but the value of such changes to patients is not necessarily clear. This article reviews conceptual and methodological issues involved in determining the value of health effects in the context of economic evaluations of epilepsy therapies. Techniques for eliciting preferences for health effects are reviewed. The limited information on preferences for epilepsy-related health states is described. Directions for further research are suggested.