Are Methods for Estimating QALYs in Cost-Effectiveness Analyses Improving?

Abstract

Objectives. The objectives of this study were to examine variations in the methods used by researchers to estimate QALYs in published cost-effectiveness analyses, and to investigate whether the methods have improved over time. Data and methods. Using a MEDLINE search, the authors identified 86 original cost-effectiveness analyses, pub lished between 1975 and 1995, that used QALYs as the measure of effectiveness. For each study, they recorded the health-state classification system, the source of the preference weights, the measurement technique, and the discount rate. The methods used were compared with the recommendations of the U.S. Panel on Cost-Effective ness in Health and Medicine. Results. Only 20% of the studies used "generic" health- state classification systems (e.g., health utilities index); 21% relied on community- based weights; 40% used formal measurement techniques (e.g., time-tradeoff method); and 88% discounted both future costs and QALYs. There was little evidence that methods had improved over time. Conclusions. The results illustrate extensive variation in the construction of QALYs in cost-effectiveness analyses and reveal that most studies have not adhered to practices now recommended by leaders in the field. There is a need for more methodologic rigor and consistency if the results of such studies are to be compared and used for purposes of allocating resources. Key words: QALYs; quality-adjusted; cost-effectiveness analysis. (Med Decis Making 1997;17: 402-408)