Comparison of the EuroQol and short form 6D in Singapore multiethnic asian knee osteoarthritis patients scheduled for total knee replacement
Version of Record online: 30 JUL 2007
Copyright © 2007 by the American College of Rheumatology
Arthritis Care & Research
Volume 57, Issue 6, pages 1043–1049, 15 August 2007
How to Cite
Xie, F., Li, S.-c., Luo, N., Lo, N.-n., Yeo, S.-j., Yang, K.-y., Fong, K.-y. and Thumboo, J. (2007), Comparison of the EuroQol and short form 6D in Singapore multiethnic asian knee osteoarthritis patients scheduled for total knee replacement. Arthritis & Rheumatism, 57: 1043–1049. doi: 10.1002/art.22883
- Issue online: 30 JUL 2007
- Version of Record online: 30 JUL 2007
- Manuscript Accepted: 3 JAN 2007
- Manuscript Received: 11 MAY 2006
- National University of Singapore. Grant Number: R-148-000-059-112
- Health-related quality of life;
To compare the EuroQol (EQ-5D) and Short Form 6D (SF-6D) among multiethnic Asian patients with knee osteoarthritis (OA) scheduled for total knee replacement in Singapore.
Patients were asked to complete questionnaires including the EQ-5D, Short Form 36, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Lequesne knee index. EQ-5D and SF-6D utility scores were calculated using the scoring algorithms developed from the UK general population. Agreement between the 2 instruments was assessed by comparing their score distributions, means, medians, intraclass correlation coefficients (ICCs), and a Bland-Altman plot. Correlations of the EQ-5D and SF-6D with WOMAC and Lequesne knee index scores were also examined.
A consecutive sample of 258 knee OA patients (127 English-speaking and 131 Chinese-speaking) participated. The mean ± SD EQ-5D utility score was 0.49 ± 0.31 (range −0.25–1.00) and the mean SF-6D utility score was 0.63 ± 0.12 (range 0.32–0.89). In a hypothetical example, this 0.14-point difference in mean utility scores yielded a difference of $10,000/quality-adjusted life year (QALY) in cost-effectiveness ratios. The score distribution was bimodal for the EQ-5D and normal for the SF-6D. This poor agreement was also demonstrated by the Bland-Altman plot and the low ICC (range 0.18–0.54). Correlations of the WOMAC and Lequesne index with the EQ-5D were higher than with the SF-6D.
Using different preference-based health-related quality of life instruments may yield different utility scores, which could have a great impact on QALY estimates. This highlights the importance of selecting appropriate instruments for economic evaluation. Additional research is needed to determine which instrument (the EQ-5D or the SF-6D) should be used in OA patients.