Are indirect utility measures reliable and responsive in rheumatoid arthritis patients?
BACKGROUND
Preference-based, generic measures are increasingly being used to measure quality of life and as sources for quality weights in the estimation of Quality Adjusted Life Years (QALYs) in rheumatoid arthritis (RA). However, among the most commonly used instruments (the Health Utilities Index 2 and 3 [HUI2 and HUI3], the EuroQoL-5D [EQ-5D], and the Short Form-6D [SF-6D], there has been little comparative research. Therefore, we examined the reliability and responsiveness of these measures and the Rheumatoid Arthritis Quality of Life (RAQoL) and the Health Assessment Questionnaire (HAQ) in a sample of RA patients.


RESULTS
Test-retest reliability was acceptable for all of the instruments with the exception of the EQ-5D. Using two external criteria to define change (a patient transition question and categories of the patient global assessment of disease activity VAS), the RAQoL was the most responsive of the instruments. For the indirect utility instruments, the HUI3 and the SF-6D were the most responsive for measuring positive change. On average, for patients whose RA improved, the absolute change was highest for the HUI3.


CONCLUSIONS
The HUI3 and the SF-6D appear to be the most responsive of the preference-based instruments in RA. However, differences in the magnitude of the absolute change scores have important implications for cost-effectiveness analyses.
Marra
Carlo A
CA
Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada.
Rashidi
Amir A
AA
Guh
Daphne
D
Kopec
Jacek A
JA
Abrahamowicz
Michal
M
Esdaile
John M
JM
Brazier
John E
JE
Fortin
Paul R
PR
Anis
Aslam H
AH
D001172:Arthritis, Rheumatoid / Q000503:physiopathology* / Q000523:psychology; D001955:British Columbia; D006801:Humans; D010147:Pain Measurement; D011594:Psychometrics / Q000295:instrumentation*; D011788:Quality of Life; D019057:Quality-Adjusted Life Years; D012219:Rheumatology / Q000295:instrumentation; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires