Incorporation of process preferences within the QALY framework: a study of alternative methods

Objective. This article explores the implications of incorporating process preferences using time tradeoff and standard gamble methods to assess the benefits of health care. Methods. Data were derived from 2 sources: a randomized controlled trial of alternative palliative care treatments (plastic stents, thermal ablation, or brachytherapy) for esophageal cancer, and a valuation survey conducted among individuals who had previously undergone curative treatment for such cancer. Costs and quality-adjusted life years (QALYs) associated with different palliative treatments in terms of health outcome values were compared to costs and QALYs based on process values derived from 3 different treatment allocation methods: 1) receipt of most preferred treatment; 2) receipt of least preferred treatment; and 3) mean process values. Results. Process values produced a different number of QALYs and QALY gains compared to those derived from health outcome values. However, treatment recommendations based on process values corresponded with those based on health outcome values: brachytherapy was identified as the more cost-effective treatment in terms of the incremental cost-per-QALY ratio by both the standard health outcome values approach and methods based on process values. These findings were supported by probabilistic analysis using the net monetary benefit framework. Conclusions. Estimation of process preferences provides additional information to policy makers in judgments over the cost-effectiveness of health care programs. These methods offer a promising alternative to standard cost-per-QALY estimation using health outcomes. However, further research examining the role of process preferences in decision making in other clinical applications appears warranted.