Where's WALY? : A proof of concept study of the 'wellbeing adjusted life year' using secondary analysis of cross-sectional survey data.
BACKGROUND
The Quality-Adjusted Life Year (QALY) is a measure that combines life extension and health improvement in a single score, reflecting preferences around different types of health gain. It can therefore be used to inform decision-making around allocation of health care resources to mutually exclusive options that would produce qualitatively different health benefits. A number of quality-of-life instruments can be used to calculate QALYs. The EQ-5D is one of the most commonly used, and is the preferred option for submissions to NICE ( https://www.nice.org.uk/process/pmg9/ ). However, it has limitations that might make it unsuitable for use in areas such as public and mental health where interventions may aim to improve well-being. One alternative to the QALY is a Wellbeing-Adjusted Life Year. In this study we explore the need for a Wellbeing-Adjusted Life Year measure by examining the extent to which a measure of wellbeing (the Warwick-Edinburgh Mental Well-being Scale) maps onto the EQ-5D-3L.


METHODS
Secondary analyses were conducted on data from the Coventry Household Survey in which 7469 participants completed the EQ-5D-3L, Warwick-Edinburgh Mental Well-being Scale, and a measure of self-rated health. Data were analysed using descriptive statistics, Pearson's and Spearman's correlations, linear regression, and receiver operating characteristic curves.


RESULTS
Approximately 75 % of participants scored the maximum on the EQ-5D-3L. Those with maximum EQ-5D-3L scores reported a wide range of levels of mental wellbeing. Both the Warwick-Edinburgh Mental Well-being Scale and the EQ-5D-3L were able to detect differences between those with higher and lower levels of self-reported health. Linear regression indicated that scores on the Warwick-Edinburgh Mental Well-being Scale and the EQ-5D-3L were weakly, positively correlated (with R(2) being 0.104 for the index and 0.141 for the visual analogue scale).


CONCLUSIONS
The Warwick-Edinburgh Mental Well-being Scale maps onto the EQ-5D-3L to only a limited extent. Levels of mental wellbeing varied greatly amongst participants who had the maximum score on the EQ-5D-3L. To evaluate the relative effectiveness of interventions that impact on mental wellbeing, a new measure - a Wellbeing Adjusted Life Year - is needed.
Division of Health SciencesWarwick Medical School, University of Warwick Coventry, Coventry, CV4 7AL, UK.
Rebecca
R
Johnson
Division of Health SciencesWarwick Medical School, University of Warwick Coventry, Coventry, CV4 7AL, UK.
David
D
Jenkinson
Division of Health SciencesWarwick Medical School, University of Warwick Coventry, Coventry, CV4 7AL, UK.
Chris
C
Stinton
Division of Health SciencesWarwick Medical School, University of Warwick Coventry, Coventry, CV4 7AL, UK.
Sian
S
Taylor-Phillips
Division of Health SciencesWarwick Medical School, University of Warwick Coventry, Coventry, CV4 7AL, UK.
Jason
J
Madan
Division of Health SciencesWarwick Medical School, University of Warwick Coventry, Coventry, CV4 7AL, UK.
Sarah
S
Stewart-Brown
Division of Health SciencesWarwick Medical School, University of Warwick Coventry, Coventry, CV4 7AL, UK. Aileen.Clarke@warwick.ac.uk.
Aileen
A
Clarke
D000293:Adolescent; D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D019057:Quality-Adjusted Life Years; D012372:ROC Curve; D057566:Self Report; D011795:Surveys and Questionnaires; D064232:Visual Analog Scale; D055815:Young Adult
EQ-5D; WALY; WEMWBS; Wellbeing