Time trends in the incidence, prevalence, and severity of rheumatoid arthritis: A systematic literature review.

INTRODUCTION: Rheumatoid arthritis (RA) generates a heavy socioeconomic burden. The ability to predict the frequency and severity of socioeconomic effects due to RA is crucial to the development of public health policies.

OBJECTIVE: To conduct a systematic literature review of data on the prevalence, incidence, and severity of RA.

METHODS: Medline, EMBASE, the Cochrane Library, and online American College of Rheumatology communications were searched for articles on the prevalence and incidence of RA, as well as on selected severity and activity criteria. Relevant articles were then selected by two investigators.

RESULTS: Frequency data are conflicting. No proof exists from cohort studies that the incidence of RA has changed over time. Overall, the prevalence of RA is stable or on the rise. Studies consistently demonstrated a decrease in severity over time, with lower activity, fewer extraarticular manifestations, a diminished need for surgery to treat joint destruction, and less severe radiological changes. The excess mortality, in contrast, despite a trend toward a decrease over time, remains significant.

CONCLUSION: The activity and deleterious effects of RA have diminished over time, in conjunction with recent therapeutic advances (new drugs and improved patient selection). However, there seems to be no decrease in the frequency of RA, which continues to induce significant excess mortality.