A quantitative approach to early rheumatoid arthritis.

The prognosis of patients with recent onset arthritis may vary from self-limiting disease to severe destructive rheumatoid arthritis (RA). In order to improve outcomes, a great deal of effort has been put into applying a diagnosis that will allow rapid initiation of treatment. The diagnosis of undifferentiated arthritis (UA) for these patients as well as the new ACR-EULAR 2010 criteria for rheumatoid arthritis (RA) are reviewed in the context of pathogenetic and clinical data available from this group of patients.