Methodological and applied concerns surrounding age-related weighting within health economic evaluation

Abstract

Economic evaluations that measure the benefits of health interventions in terms of units of health gain inevitably require decision-makers to make judgments about the ‘value for money’ of those health gains. Decision-making bodies have also commonly returned to the position that a unit of health gain, such as an additional quality-adjusted life year, is of equal value regardless of the characteristics of the recipient. This paper focuses on whether and how health gains in economic evaluation should be differentially weighted by age of recipient. The paper presents a structured overview of evidence from the revealed preference and stated preference literature in this area. It discusses a number of methodological issues raised by differential weighting of health gains by age of recipient. These include identifying appropriate samples for the derivation of age-related weights, methodological issues surrounding the application of the quality-adjusted life year measure, the relative merits of alternative valuation techniques for weighting exercises, the impact of context and design effects on derived values and operational concerns surrounding the application of age-related weights within economic evaluation. The paper ends with pointers for potential future research in this area.

Keywords::

• age
• distributional
• economic evaluation
• preferences
• weighting

Acknowledgements

The author is grateful to colleagues for their suggestions and comments on the manuscript.

Disclaimer

The views herein expressed are those of the author and not necessarily those of the funding bodies.

Financial & competing interests disclosure

The Warwick Clinical Trials Unit, University of Warwick, benefited from facilities funded through the Birmingham Science City Translational Medicine Clinical Research and Infrastructure Trials Platform, with support from Advantage West Midlands. The author has no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Economic evaluations that measure the benefits of health interventions in terms of units of health gain require decision-makers to make judgments about the ‘value for money’ of those health gains.

• Decision-making bodies in many jurisdictions commonly require unitary weights to be applied to units of health gain, such as an additional quality-adjusted life year, regardless of the characteristics of the recipient.

• Empirical evidence suggests that some people may be willing to give greater weight to health gains by certain population groups, such as those in more severely impaired health states, and those with shorter remaining life expectancy.

• There is a growing body of evidence from revealed preference and stated preference studies, which generally indicates that individuals place greater value on health gains by younger people. There is also some evidence for an inverted U-shaped relation between age and the values placed on health gain.

• The literature around age weighting units of health gain is constrained by a number of methodological factors.

• Future research should aim to estimate distributional weights for health gains, such as an additional quality-adjusted life year, according to combinations of characteristics of potential relevance to decision-makers, for example, age in combination with gender, or age in combination with socioeconomic status.

• Future research should consider whether and how age-related weights are also applied to health benefits foregone as a result of health service activities displaced by adoption decisions.