MEASURING HEALTH-RELATED QUALITY-OF-LIFE IN RHEUMATOID-ARTHRITIS - VALIDITY, RESPONSIVENESS AND RELIABILITY OF EUROQOL (EQ-5D)

The EuroQo1 (EQ-5D) generic health index comprises a five-part questio nnaire and a visual analogue self-rating scale. The questionnaire may be used as a health index to calculate a 'utility' value or as a healt h profile. The validity, reliability and responsiveness of EQ-5D were tested in 233 patients with rheumatoid arthritis stratified by functio nal class. EQ-5D demonstrated moderate to high correlations with measu res of impairment and high correlations with disability measures. Step wise regression models showed that EQ-5D utility values and visual ana logue scores were explained best as a function of pain, disability, di sease activity and mood (R-2 similar to 70%), although other variables (side-effects, years of education) were required to explain the visua l analogue scores. The EQ-5D health index and visual analogue scale ar e more responsive than any of the other measures, except pain and doct or-assessed disease activity. The reliability of the EQ-5D index and E Q-5D visual analogue scale is as good or better than that of all other instruments except the Health Assessment Questionnaire. Some patients with severe long-standing disease had health states which attracted u tility values below zero, i.e. from a societal perspective they were r egarded as being in states 'worse than death'. The practical and ethic al implications of these utility valuations are discussed, and at pres ent the utility values should be used and interpreted with caution. Wi th this caveat, EQ-5D is simple to use, valid, responsive to change an d sufficiently reliable for group comparisons. It is of potential use as an outcome measure in clinical trials, audit and health economic st udies, but further work is required on its performance in other clinic al contexts and on the interpretation of the utility values.