Adjustment of foreign EQ-5D-3L utilities can increase their transferability

Foreign utilities of the EQ-5D-3L (3-level version of the EuroQol-5 Dimension of health questionnaire) are not readily transferrable to economic evaluations conducted from a national perspective. It has been advised to avoid transferring mean utilities from one country to another without adjusting them; yet no such method exists.

The present study aimed to develop a method for adjusting mean utilities to increase their transferability from one country to another.

Seven datasets containing EQ-5D-3L answers were valued using value sets from four countries: the UK, the Netherlands, Germany, and Spain. Hereby, seven mean utility values were obtained for each country. This allowed for three pairwise comparisons: 1) UK mean values vs Dutch mean values; 2) UK mean values vs German mean values; and 3) UK mean values vs Spanish mean values. For each of these three comparisons, a regression model was fitted using the mean UK utilities as the dependent variable and the other country's mean utilities as the independent variable. The coefficients from the three regression models were validated using results from a published article containing mean utilities obtained by valuing the EQ-5D-3L data using all four value sets.

The findings suggested that adjustment of foreign utilities may increase transferability between countries where value sets are not comparable. It was possible to adjust the mean utilities valued by the Dutch and German value sets to make them reflect mean UK utilities as there were substantial differences between these value sets. Transferability of the Spanish mean utility values was not improved as the Spanish and UK value sets are sufficiently similar.

It is feasible to adjust foreign mean utilities of the EQ-5D-3L to make them reflect national preferences for health.