The course of established rheumatoid arthritis.

Rheumatoid arthritis (RA) varies over time in individual patients and there are marked differences between patients in its impact and progression. The course of RA is therefore unique to each individual patient and is affected by the overall pattern of disease; many patients have classical polyarticular disease but there is also a range of subtypes, such as fibromyalgic and polymyalgic disease. Some patients with RA enter a period of sustained remission; this varies between 10% and 36% of cases; its frequency is mainly influenced by the different approaches to studying RA patients over time, and does not represent a true difference in disease outcome. Most patients have persisting synovial inflammation and disease activity scores average between 3 and 4; there is some evidence that inflammation is less marked in late RA. Persisting synovitis results in increasing disability - this worsens by an average of 0.6% each year - and in joint damage, which increases by an average of 2% each year. Comorbidities and extra-articular features are commonplace: about one-third of patients, respectively, have associated cardiovascular disease, lung disease or extra-articular features, although severe extra-articular problems like vasculitis affect only about 10% of patients. Some aspects of the course of RA are influenced by genetic risks; currently these are only weak predictors but it is anticipated their value will increase with time.