Estimating the prevalence and disease characteristics of rheumatoid arthritis in Tehran: A WHO -ILAR COPCORD Study (from Iran COPCORD study, Urban Study stage 1)

To estimate the prevalence and characteristics of Rheumatoid Arthritis (RA) in an urban area of Tehran. A total of 50 clusters were randomly selected in Tehran and 10291 subjects completed the COPCORD Core Questionnaire during 2004 and 2005. Patients with rheumatic complaints were examined and diagnosed by subspecialty fellows in rheumatology. Laboratory and radiology tests were also performed if required. A total of 35 subjects (5 men and 30 women) were diagnosed with RA, with a prevalence of 0.33% (95% CI: 0.22-0.46). Our results demonstrated that RA was six times more common in women than men. The mean age (± SD) of patients was 52.3 (± 17.6) years. Morning stiffness > 1 hour was reported in 37.1% of patients. Rheumatic signs were commonly found in wrist (60%), knee (60%), metacarpophalangeal (48.6%) and proximal interphalangeals of hand (40%). Approximately 46% of patients had difficulty carrying out daily activities. According to our study, the prevalence of RA in Iran seems to be lower than western countries. However, the prevalence of RA in Iran seems to be approximately in the middle point comparing the APLAR region (from 0.7% in Australia (rural) to 0.12% in Thailand).