Health Years in Total (HYT): A new health objective function for cost-effectiveness analysis

Abstract: The standard effectiveness measure in cost-effectiveness (CEA) or cost-utility analysis is the quality-adjusted life-year (QALY). Despite the important advantages of QALY – capturing both life expectancy and health-related quality of life impacts and enabling comparisons across interventions and disease areas – specific distribution issues generated by the use of QALY present a critical challenge that has resulted in the exclusion of its use in some public decision making (e.g. US Medicare) on health care in the US. Alternatives to QALY (such as Equal Value of Life, EVL) have not gained traction as their use raises other efficiency issues. For example, EVL fails to recognize quality of life gains during added years of life. We present a new metric for effectiveness for CEA, Health Years in Total (HYT), that overcomes both the distributional issues raised by QALYs and the efficiency challenges of EVL. The HYT framework fundamentally separates life-expectancy changes and quality of life changes in an additive scale. We provide conceptual and theoretic arguments for use of HYT and illustrate their performance against QALYs and EVL. We also present methods to calculate HYT in a CEA model, derive CEA thresholds for HYT corresponding to the QALY–based thresholds in the US, and study the policy implications for the use of HYT using recently published technology evaluations. The HYT framework may provide a viable alternative to both the QALY and the EVL; its application to diverse healthcare technologies and stakeholder assessment are important next steps in its development and evaluation.