Relationship of EQ-5D quality of life with the presence of co-morbidity and extra-articular features in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is associated with extra-articular features (ExRA) and other co-morbidities. The aim of this study is to quantify their relative contribution to quality of life (QOL) in patients with RA. A consecutive series of 114 ambulatory RA patients aged between 40 and 65 years were assessed by a research nurse on a single occasion. Assessment included a patient questionnaire (including EQ-5D), medication review and fasting venous blood sample. Medical records were reviewed by a rheumatologist for co-existing conditions. Multiple linear regression was used to adjust mean differences in EQ-5D in the presence/absence of co-existing conditions for age, sex, university education, arthritis duration, rheumatoid factor, erythrocyte sedimentation rate, current disease-modifying drug therapy, previous hand joint erosions and joint surgery. Mean age was 54 years (82 % female) and median arthritis duration 10 years. Unadjusted EQ-5D was -0.09 (95 % CI -0.18 to -0.01) lower in patients with any co-existing condition. EQ-5D scores were inversely correlated with the overall number of co-existing conditions (Spearman's rho -0.31, p = 0.001), number of co-morbidities (rho -0.22, p = 0.02) and number of ExRA features (rho -0.22, p = 0.02). There was a linear trend of lower EQ-5D with increasing number of co-existing conditions (p = 0.003). EQ-5D was -0.18 (95 % CI -0.33 to -0.02) lower in the presence of more than two co-existing conditions compared to none. Co-morbidity and ExRA features were associated with comparable adjusted reductions (-0.05 vs. -0.06) in EQ-5D scores. A wide range of co-existing conditions are associated with poorer QOL in patients with RA.