Measurement of the quality of life in rheumatic disorders using the EuroQol

Abstract

The EuroQol is a validated quality of life (QOL) scale that has been used in population and clinical studies, and has been reported in patients with rheumatoid arthritis (RA). It is short, simple to complete, and might be suitable for surveys of rheumatic disease patients. The properties of this instrument were investigated in a postal survey of 1372 rheumatic disease patients, including 537 with RA, 319 with osteoarthritis (OA) and 516 with fibromyalgia. In addition, simultaneous measurements of functional disability, pain, psychological status, global severity and demographic characteristics were made. EuroQol scores (0.57) were significantly lower than VAS health state scores (0.67) and arthritis-related global severity scores (0.62). QOL was similar in RA and OA, but lower in fibromyalgia, across all instruments. The distribution of EuroQol scores had many gaps and was not continuous. EuroQol did not reflect VAS QOL scores at EuroQol levels below 0.5, and the mean score difference between the instruments below that level was 0.43. Many patients with low EuroQol scores (including some with health states that were 'worse than death') had high VAS scores. These differences appear to have arisen because disability, pain and depression questions ask about mild or moderate problems, but not both, thereby forcing scale compression in the mid ranges. In addition, the 'severe' value is so extremely abnormal that few patients endorse it. Finally, penalty scores are applied to those with at least one maximally abnormal score. The scoring properties and distributional aspects of the EuroQol indicate substantial problems in its use in rheumatic disease patients.