The gap effect: discontinuities of preferences around dead

Area of Science:

• Health Economics
• Psychometrics
• Quality of Life Research

Background:

• Assessing health states perceived as worse than death presents significant challenges and controversy in healthcare valuation.
• Understanding patient preferences for extremely poor health states is crucial for accurate health outcome measurement.

Purpose of the Study:

• To investigate the valuation of health states when they are perceived as worse than death.
• To compare differences between adjacent health states with differences involving states considered worse than death using established valuation methods.

Main Methods:

• Secondary analysis of EuroQol EQ-5D data from the Measurement of Valuation and Health (MVH) study.
• Utilized Visual Analog Scale (VAS) and Time Trade-Off (TTO) methods to elicit preferences for 43 distinct health states from 3395 respondents.
• Ranked health states by VAS and TTO values and calculated differences between adjacent states.

Main Results:

• Visual Analog Scale (VAS) values showed consistent differences between ordered health states.
• Time Trade-Off (TTO) values revealed significant gaps around the 'dead' state, for both positive and negative valuations.
• Data from 2997 respondents were analyzed, highlighting discrepancies in how VAS and TTO capture extreme health states.

Conclusions:

• The Time Trade-Off (TTO) method effectively identifies health states valued as worse than death, unlike the Visual Analog Scale (VAS).
• Current Quality-Adjusted Life Year (QALY) models require expansion to accurately incorporate utilities for states worse than death.
• The descriptive validity of existing QALY models is limited for extremely poor health states and those with maximal endurable durations.