PAM5: INVESTIGATING THE CONSTRUCT VALIDITY OF A DISEASE SPECIFIC AND A GENERAL QUALITY OF LIFE INSTRUMENTS OF PATIENTS WITH RHEUMATOID ARTHRITIS

Abstract

OBJECTIVES: Quality of life is a key parameter in describing the health status patients of rheumatoid arthritis. Construct validity of a generic (EQ-5D) and a disease specific (RAQoL) quality of life instrument was tested with the intention of further use in clinical and health economic trials and burden of disease studies in Hungary. METHODS: RAQoL and EQ-5D have been recently adapted into Hungarian. Authors analysed the demographic and QoL data from a cross-sectional postal survey of patient with rheumatoid arthritis. The convergent validity of EQ-5D, RAQoL scores has been compared to functional measurement scores from the Health Assessment Questioner (HAQ). Pearson correlation coefficients were used to assess the level of association. RESULTS: 81 patients participated in the study. Mean age of the sample was 57.3 (SD = 10.1) years, 89% (n = 72) were female. The average disease duration among patients was 14.5 (SD = 10.6) years. RAQoL scores were relatively strongly correlated (Pearson coefficient = 0.662) with HAQ scores. The EQ-5D index scores showed higher correlation (0.627) with HAQ than the Visual Analogue Scale of EQ-5D (0.463). The Pearson Correlation Coefficient between RAQoL and EQ-5D index scores was 0.515, and between RAQoL and EQ-5D VAS scores was 0.396. CONCLUSIONS: Results suggest that the Hungarian RAQoL is a valid instrument of measuring QoL of rheumatoid arthritis patients. The EQ-5D index provides also appropriate results, and can be proposed for cost-utility analyses. However EQ-5D VAS scores are not recommended to describe the QoL of patients with rheumatoid arthritis.