Equity in health care prioritisation: an empirical inquiry into social value

The value of QALY gains for different patients may be recalculated using equity weights, but it is unclear which interpretation of equity should be used: severity of illness, fair innings or proportional shortfall. We set up an experiment to analyze which of these equity concepts best reflects people's distributional preferences. Sixty respondents assigned a priority rank to the treatment of 10 conditions using the paired comparison technique. We described these real-life conditions by their actual QALY profiles, i.e. in terms of age, disease free period, duration of disease, quality of life, and life years lost. Next we determined the priority rank order of the 10 conditions by the three equity concepts, using the weights that each equity concept attributes to the different units of the QALY profile describing the 10 conditions. To explore the social interpretation of equity, we compared the observed and theoretical rank orderings using Spearman correlations. All correlations were significant at a 0.05 level. Fair innings best predicted the observed rank order of the 10 conditions (r=0.95). Weaker correlations were found for proportional shortfall (r=0.82) and severity of illness (r=-0.65). This result calls attention to health policy, because actual health care decisions often reflect concerns of severity of illness. This raises the question if health care decision makers evaluate the claims of different patients for health care by appropriate criteria.