Modelling the relationship between the WOMAC osteoarthritis index and EQ-5D

Health and Quality of Life Outcomes

Antonio Escobar Martinez¹  Monica Hernandez Alava²  Allan Wailoo² 

[1] Red de Investigación en Servicios de Salud y Cronicidad (REDISSEC), Hospital Universitario Basurto, Bilbao, Spain;Health Economics and Decision Science, School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK

关键词: Statistical methods;    Osteoarthritis;    Mapping;    WOMAC;    EQ-5D;   

Others  :  815075
DOI  :  10.1186/1477-7525-12-37

 received in 2013-07-01, accepted in 2014-03-05,  发布年份 2014

【 摘 要 】

Objective

Economic evaluation typically is conducted using health state utilities to estimate treatment benefits. However, such outcomes are often missing from studies of clinical effectiveness. This study aims to bridge that gap by providing appropriate methods to link values from the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) to the EQ-5D utility instrument.

Method

Patients from a large registry of Spanish patients (n = 7072 observations) with knee or hip osteoarthritis who completed both WOMAC and EQ-5D was used. A mixture model approach was used based on distributions bespoke to the EQ-5D UK value set to estimate EQ-5D as a function of WOMAC pain, stiffness and function subscores.

Results

A five class mixture model provides very close fit to the observed data at all levels of disease severity. The overall mean (0.542 vs 0.542), median (0.620 vs 0.636) and the percentage of observations at full health (15 vs 14.8) were very similar between the observed data and the estimated model respectively. Stiffness has limited relationship to EQ-5D, whereas functional disability and pain are strong predictors.

Conclusion

EQ-5D can be reliably estimated from WOMAC subscale scores without any systematic bias using these results.

【 授权许可】

   
2014 Wailoo et al.; licensee BioMed Central Ltd.

【 图 表 】

Figure 1.

Figure 2.

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