ORIGINAL RESEARCH ARTICLE Validation of the Underlying Assumptions of the Quality-Adjusted Life-Years Outcome: Results from the ECHOUTCOME European Project Ariel Beresniak • Antonieta Medina-Lara • Jean Paul Auray • Alain De Wever • Jean-Claude Praet • Rosanna Tarricone • Aleksandra Torbica • Danielle Dupont • Michel Lamure • Gerard Duru Ó Springer International Publishing Switzerland 2014 Abstract Background Quality-adjusted life-years (QALYs) have been used since the 1980s as a standard health outcome measure for conducting cost-utility analyses, which are often inadequately labeled as ‘cost-effectiveness analyses’. This synthetic outcome, which combines the quantity of life lived with its quality expressed as a preference score, is currently recommended as reference case by some health technology assessment (HTA) agencies. While critics of the QALY approach have expressed concerns about equity and ethical issues, surprisingly, very few have tested the basic methodological assumptions supporting the QALY equation so as to establish its scientific validity. Objectives The main objective of the ECHOUTCOME European project was to test the validity of the underlying assumptions of the QALY outcome and its relevance in health decision making. Methods An experiment has been conducted with 1,361 subjects from Belgium, France, Italy, and the UK. The sub- jects were asked to express their preferences regarding var- ious hypothetical health states derived from combining different health states with time durations in order to com- pare observed utility values of the couples (health state, time) and calculated utility values using the QALY formula. Results Observed and calculated utility values of the cou- ples (health state, time) were significantly different, con- firming that preferences expressed by the respondents were not consistent with the QALY theoretical assumptions. Conclusions This European study contributes to establish- ing that the QALY multiplicative model is an invalid measure. This explains why costs/QALY estimates may vary greatly, leading to inconsistent recommendations relevant to provid- ing access to innovative medicines and health technologies. HTA agencies should consider other more robust methodo- logical approaches to guide reimbursement decisions. Key Points Underlying assumptions of the quality-adjusted life- year (QALY) are not validated by an experiment conducted in four European countries. The fact that the QALY metric is an invalid measure explains why costs/QALY estimates may vary greatly. Health technology assessment agencies should consider other current and new methodological approaches for healthcare decision making. A. Beresniak (&) Data Mining International, Route de l’Ae ´roport, 29-31, CP 221, 1215 Geneva 15, Switzerland e-mail: aberesniak@datamining-international.com A. Beresniak LIRAES, Paris-Descartes University, Paris, France A. Medina-Lara Exeter University, Exeter, UK A. Medina-Lara CERGAS, Bocconi University, Milan, Italy J. P. Auray Á G. Duru Cyklad Group, Lyon, France A. De Wever Á J.-C. Praet Universite ´ Libre de Bruxelle, Brussels, Belgium R. Tarricone Á A. Torbica Department of Policy Analysis and Public Management, Bocconi University, Milan, Italy D. Dupont Á M. Lamure Claude-Bernard University, Lyon, France PharmacoEconomics DOI 10.1007/s40273-014-0216-0