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.