Objective: To analyze associations between clinical status of patients with rheumatoid arthritis (RA) and the gross domestic product (GDP) of their resident country.
Methods: The Quantitative Standard Monitoring of RA (QUEST-RA) cohort includes clinical and questionnaire data from 6,004 patients who were seen in usual care at 70 rheumatology clinics in 25 countries as of April 2008, including 18 European countries. Demographic variables, clinical characteristics, RA disease activity measures including the Disease Activity Score (DAS28), and treatment related variables were analyzed according to GDP per capita, including 14 "high gpd" countries with GDP per capita >24K USD, and 11 "low gpd" countries with GDP per capita <11K USD.
Results: Disease activity DAS28 ranged between 3.1 and 6.0 among the 25 countries, and was associated significantly with GDP [r= -0.78 (95% CI -0.56 to -0.90), r2 = 61%]. Disease activity levels differed substantially between "high gdp" and "low gdp" countries at much greater levels than according to whether patients were currently taking or not taking methotrexate, prednisone, and/or biologic agents.
Conclusions: Clinical status of patients with RA was correlated significantly with GDP among 25 mostly European countries according to all disease measures, associated only modestly with current use of anti-rheumatic medications. The burden of arthritis appears substantially greater in "low gdp" than in "high gdp" countries. These findings may alert health care professionals and designers of health policy toward improving clinical status of patients with RA in all countries.