Objective. The aim of this study is to analyze the capacity of three demographic variables - age, sex, and formal education level - as well as disease duration to explain variation in 7 Core Data Set variables and 4 indices used to assess rheumatoid arthritis (RA), in a cohort of Korean patients seen in usual care. Methods. All RA Core Data Set measures were collected in usual care of 397 RA patients, including tender/swollen joint counts (TJC, SJC) 28, physician global estimate of status, erythrocyte sedimentation rate, C-reactive protein, and a multidimensional health assessment questionnaire to assess physical function, pain, and patient global estimate of status (PATGL). Four indices were computed: disease activity score with 28 joint count (DAS28), simplified disease activity index (SDAI), clinical disease activity index (CDAI), and routine assessment of patient index data 3 (RAPID3). Descriptive statistics and multivariate generalized linear models were used in data analysis. Results. Patients with lower education had higher scores, indicating greater severity, for all 7 Core Data Set measures and 4 indices (significant for TJC, function, pain, PATGL, DAS28, SDAI, CDAI, RAPID3). In a series of regressions that included age, sex, disease duration, and education, formal education level was the only significant variable to explain variation in TJC, pain, PATGL, physician global estimate of status (DOCGL), DAS28, SDAI, CDAI, and RAPID3. Conclusion. Significant associations with education were found in Korean RA patients according to most RA Core Data Set measures and 4 indices. Education was more likely than age, sex, or disease duration to explain variation in most measures and indices. (J Rheum Dis 2015;22:231-237)

Keywords: Rheumatoid arthritis, Social class, Education