Estimating an exchange rate between the EQ5D-3L and ASCOT

Please note, there are no tables and figures in this report and we have no further iteration of the report to upload.

The aim was to estimate an exchange rate between the EQ-5D-3L and ASCOT using a new preference based method.

These measures are useful for examining cost-effectiveness within sectors, but there is a policy need to aggregate benefits across sectors to understand overall benefits and compare across sectors to assess relative value for money. Although these measures are scored on the QALY scale using similar versions of time trade off, the upper anchors differed which may result in differences.

We used a value based mapping approach to estimate the exchange rate. A sample of health states from each measure was valued using TTO by 200 members of the UK adult general population. The generic upper anchor was “the best life imaginable” ensuring the two measures were valued on a common scale.

The relationship between the measures is a linear transformation with an intercept of -0.0404 and gradient of 0.9648 for moving from ASCOT to EQ-5D-3L. This enables the QALY gain generated by ASCOT to be comparable to that for the EQ-5D across different interventions.

This method could be applied to other measures, such as the ICECAP and also provide another method for moving between generic and condition specific measures in health care.