Diagnostic and Therapeutic Opportunities in Undifferentiated Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease that may have a high impact on patients’ quality of life, because it is associated with disability, comorbidities, and an increased mortality rate [1]. In the last 10 years, it has been recognized that RA needs to be diagnosed early and treated promptly with disease-modifying antirheumatic drugs (DMARDs) in order to successfully interfere with the disease process. This new treatment paradigm, in combination with new therapeutic options, has already improved the prospects for patients with RA, with reductions in the levels of joint destruction, disability, and mortality. While rheumatologists can now successfully reduce the degree of disease activity in patients with RA, the ultimate challenge for the future is to initiate therapy in such an early phase that the actual development of RA is prevented. Clearly, this will require patients to be treated before the disease is fully developed. It is plausible that in an early phase of the disease, the mechanisms that drive chronicity are less established and that interference with the disease process will induce remission more easily. For patients to be treated before the disease is fully developed, rheumatologists require two tools: first, a means of identifying patients who will develop RA; and, second, drugs that are proven to be effective in preventing the development of RA. It is conceivable that, in the coming years, clinical trials will be designed to assess treatment efficacy in patients with early undifferentiated arthritis (UA). This article appraises the definition of UA, the natural course of UA, clinical characteristics that predict progression from UA to RA, and pathophysiological differences between UA and RA. In addition, findings from the first trial investigating the effect of DMARDs in patients with UA are presented.