Considering Severity in Health Technology Assessment: Can We Do Better?

There is strong evidence that individuals and the public assign relatively greater value to health gains from relatively more severe health states. This preference is increasingly reflected in health technology assessment, with some consideration of severity incorporated by health technology assessment bodies in, among others, The Netherlands, England and Wales, Norway, Sweden, and the United States. If a societal “severity premium” is to be considered fairly and consistently, we argue that a more explicit and quantitative approach is needed. We highlight drawbacks of categorical approaches, especially discontinuities between severity categories that arguably violate concepts of vertical equity, and argue that a more continuous approach to understanding severity is needed. We also note challenges to more explicit approaches, including implications of a lower threshold for less severe conditions and the relative complexity of calculating a continuous severity adjustment.