Prevalence of Rheumatoid Arthritis in the Southern Part of Denmark

The aim of the present study was to estimate the prevalence of rheumatoid arthritis in the southern part of Denmark. Using a screening questionnaire, telephone interview, register data, and a clinical examination cases were ascertained from a random sample of 4995 individuals over the age of 15. As case definition we used the original and modified 1987 American College of Rheumatology classification criteria. The overall point prevalence was 0.26% (95% confidence interval: 0.13-0.39) in the total sample and 0.35% (95% confidence interval: 0.17-0.52) among the responders; the cumulative prevalence was 0.75% (95% confidence interval: 0.52-0.97) in the total sample and 0.92% (95% confidence interval: 0.62-1.21) among the responders. The cumulative prevalence was higher than in other studies combining the results of a survey with register data. The point prevalence was underestimated due to low participation rate in the clinical examination and remission among the participants.