Prevalence of rheumatic symptoms, rheumatoid arthritis, ankylosing spondylitis, and gout in Shanghai, China: a COPCORD study.

OBJECTIVE To carry out a cross-sectional survey on prevalence of musculoskeletal symptoms, rheumatoid arthritis (RA), ankylosing spondylitis (AS), and gout. METHODS In Shanghai, 4 communities comprising 7603 inhabitants over 15 years of age in an urban population were randomly selected from 13 communities. Interviews were conducted from September 1997 to March 1998 by trained physicians using the COPCORD Core Questionnaire. Physical and radiographic examinations and serologic tests were carried out when required to classify categories of rheumatic diseases. The diagnoses of RA, systemic lupus erythematosus (SLE), and gout were based on American Rheumatism Association criteria. The diagnosis of AS strictly followed the modified New York criteria of 1984. Crude prevalence rates were standardized according to a standard Chinese population for age and sex structure. RESULTS A total of 6584 adults (3394 women, 3190 men) were interviewed, and response rate was 86.6%. The age and sex standardized prevalence rate of rheumatic symptoms at any site amounted to 13.3% (95% CI 12.5-14.1%). Symptoms occurred more frequently in the following sites: knee 7.0% (95% CI 6.4-7.6%), lower back 5.6% (95% CI 5.0-6.2%), shoulder 4.7% (95% CI 4.2-5.2%), and neck 2.4% (95% CI 2.0-2.8%). Women complained of rheumatic symptoms more frequently than men. The standardized rates of RA, AS, gout, symptomatic knee osteoarthritis, and soft tissue rheumatism were 0.28% (95% CI 0.15-0.41%), 0.11% (95% CI 0.03-0.19%), 0.22% (95% CI 0.11-0.33%), 4.1% (95% CI 3.6-4.6%), and 3.4% (95% CI 3.0-3.8%), respectively. Two cases of SLE, one case of dermatomyositis, and one case of systemic sclerosis were found. CONCLUSION Compared with rates in European and Western countries the prevalence rates of RA, AS, and gout are low in Shanghai, China, although the prevalence rates of rheumatic symptoms are high.