To define the prevalence of rheumatoid arthritis (RA) from the data of an epidemiological study.
During a questionnaire survey of 37057 adults of Russia, patients with complaints of articular swelling (n = 4975) were selected; of the latter a group (n = 3420) was randomly formed to be clinically examined by rheumatologists in order to detect RA. The 1987 ACR criteria were used for its diagnosis.
According to the data of the questionnaire survey, RA was diagnosed in 159 (4.6%) of the 3420 patients with complaints of articular swelling. The prevalence of RA in Russia averaged 0.61%. Among the respondents who complained about articular swelling during the questionnaire survey, 258 (7.5%) respondents considered to have RA before rheumatological examination. While comparing the diagnoses reported by the respondents during the survey and the final diagnosis established by a specialist, RA was confirmed only in 61 (24%) patients. Out of all the identified patients with RA (n = 159), only 61 (38%) were aware of their diagnosis. In RA patients with less than one-year articular complaints (n = 24), 17% were familiar with their diagnosis; the diagnosis was first made in the others (n = 20). Among the patients with long-term articular complaints (n = 135), 42% were aware of their diagnosis.
The epidemiological survey indicated that the number of patients with RA were twice higher than those given in the official statistics of the Russian Federation (671,000 versus 300,000, respectively). In outpatient practice, RA is correctly diagnosed only in 38% of cases. There is a significant hyperdiagnosis of this disease. The duration of articular complaints affects the establishment of the diagnosis of RA.