Estimating an exchange rate between the EQ-5D-3L and ASCOT

Area of Science:

• Health Economics
• Outcome Measurement
• Preference-Based Valuation

Background:

• The EQ-5D-3L and Adult Social Care Outcome Tool (ASCOT) are crucial for cost-effectiveness analyses in health and social care, respectively.
• A policy need exists to compare benefits and value for money across these sectors.
• Standard statistical mapping is inadequate due to differing conceptualizations of quality of life between EQ-5D-3L and ASCOT.

Purpose of the Study:

• To estimate an exchange rate between the EQ-5D-3L and ASCOT using preference-based mapping.
• To facilitate cross-sectoral comparisons of cost-effectiveness by establishing a common metric.
• To utilize common time trade-off (TTO) valuations as the basis for the mapping.

Main Methods:

• Employed a preference-based mapping approach using common TTO valuations for both EQ-5D-3L and ASCOT.
• Collected TTO values for a sample of health states from both measures from 200 UK adults.
• Utilized regression analyses to derive simultaneous equations for estimating the EQ-5D-3L and ASCOT relationship.

Main Results:

• A linear transformation was established for converting ASCOT values to EQ-5D-3L values, with an intercept of -0.0488 and a gradient of 0.978.
• This derived exchange rate enables the direct comparison of quality-adjusted life year (QALY) gains between interventions measured by ASCOT and EQ-5D-3L.

Conclusions:

• An exchange rate between ASCOT and EQ-5D-3L was successfully estimated using preference-based mapping without compromising the measures' descriptive systems.
• This research advances preference-based mapping methodologies by employing TTO as a common metric for inter-measure valuation.
• The findings support improved cross-sectoral economic evaluations in health and social care.