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The impact of adding an extra dimension to a preference-based measure
John Brazier1, Donna Rowen, Aki Tsuchiya
1University of Sheffield, UK. j.e.brazier@sheffield.ac.uk
Social Science & Medicine (1982)
|June 22, 2011
Summary
Adding a pain dimension to health measures significantly alters utility values, impacting Quality Adjusted Life Years (QALYs) comparisons. This highlights the need for comprehensive descriptive systems in health preference-based measures.
Area of Science:
- Health Economics
- Psychometrics
- Patient-Reported Outcomes
Background:
- Comparing Quality Adjusted Life Years (QALYs) across different health measures is challenging.
- Excluding key health dimensions from descriptive systems can affect measure validity.
- Condition-specific preference-based measures (CSPBMs) may omit important dimensions like pain.
Purpose of the Study:
- To assess the impact of adding a generic pain/discomfort dimension to an asthma-specific CSPBM (AQL-5D).
- To investigate how including pain affects the valuation of health states and the coefficients of other dimensions.
- To evaluate the implications for comparing QALYs generated by different preference-based measures.
Main Methods:
- Valued health states from the AQL-5D with and without an added pain/discomfort dimension.
- Used an interviewer-administered time trade-off method with a UK general public sample (n=180).
- Collected 720 valuations for health states across different pain severities.
Main Results:
- The added pain/discomfort dimension had a significant and large coefficient.
- Including pain altered the coefficients of other dimensions, with varying impact by dimension and severity.
- Mild/moderate pain increased utility values, while extreme pain decreased them for asthma patients.
Conclusions:
- The impact of different health dimensions on preferences may not be simply additive.
- Comparability of QALYs across measures is questionable if dimensions are omitted.
- Preference-based measures must include all relevant dimensions in their classification systems for valid comparisons.
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