Valuations of EQ-5D health states: could United Kingdom results be used as informative priors for the United States

Valuations of health state descriptors such as the generic EuroQol five-dimensional (EQ-5D) or the six-dimensional short form (SF-6D) have been conducted in different countries. There is a scope to make use of the results in one country as informative priors to help with the analysis of a study in another, for this to enable better estimation to be obtained in the new country than analysing its data separately. This article analyses data from 2 EQ-5D valuation studies where, using similar time trade-off protocols, values for 42 common health states were elicited from representative samples of the US and UK general adult populations. We apply a nonparametric Bayesian method to improve the accuracy of predictions of the US population utility function where the UK results were used as informative priors. The results suggest that drawing extra information from the UK data produces a better estimation of the US population utility than analysing its data separately. The implications of these results will be extremely crucial in countries where valuation studies are limited.