Objective: To investigate the clinical, laboratory, radiologic characteristics, and joint involvement of rheumatoid arthritis (RA) in Korean. Methods: We retrospectively reviewed initial medical records of 210 patients diagnosed as rheumatoid arthritis in Seoul, Sanggye, and Ilsan Paik Hospital, Inje University. Evaluation included age, sex, disease duration, duration of morning stiffness, joint involvement, the number of tender and swollen joints, rheumatoid factor, erythrocyte sedimentation rate (ESR), C- reactive protein (CRP), and bony erosion in simple X-ray. Results: In total 210 patients, mean age was 50.1±13.5 years, and male to female ratio was 1 to 5.6. Mean duration of arthritis was 51.8±72.6 months and positive rate of rheumatoid factor was 66.7%. Mean time interval between symptom onset and first visit was 14.1±19.1 months. Bony erosion rate was 15.3% in early RA patients, who had been diagnosed as RA within 1 year. The order of frequency of joint involvement was as the follows; metacarpophalangeal (MCP) joints, wrist joints, proximal interphalangeal (PIP) joints, metatarsophalangeal (MTP) joints, ankle joints, and knee joints. It was noted that the joints on the right and left sides behaved in like fashion. This pattern was not different with early RA. The titer of rheumatoid factor showed poor correlations with variables of clinical activity (ESR, CRP, duration of morning stiffness, and number of tender and swollen joints).Conclusion: In Korea, clinical manifestations and joint involvement of RA patients were not different from other published studies. The most commonly involved joints are MCP joints, wrist joints, PIP joints, and MTP joints.

Keywords: Rheumatoid arthritis, Clinical characteristics, Joint involvement