Over the last several years the two pre-eminent professional societies representing rheumatology, the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR), have been discussing increasing their collaboration in areas of interest to rheumatologists worldwide. These discussions resulted in a letter of agreement in 2008 on the framework whereby the two organisations would work together to develop disease classification criteria as well as recommendations for conducting of clinical trials. To enhance communication between the two organisations, ACR representatives now sit on the EULAR Standing Committee for Clinical Affairs and the EULAR Standing Committee of Epidemiology, and EULAR representatives now sit on the ACR Criteria Subcommittee and Quality of Care Committee.

The first result of this effort was the joint publication, in Annals of the Rheumatic Diseases and Arthritis Care & Research, of the recommendations on reporting disease activity in clinical trials of patients with rheumatoid arthritis (RA).1 2 This document was important in that it delineated the minimal standards necessary for clinical trials evaluating new therapeutics in RA. Several collaborative projects are under way on RA, and also on gout, scleroderma, myositis and vasculitis. The positive aspects of developing a consensus between the dominant voices in world of rheumatology are self-evident.

The recent initiative to revise the ACR classification criteria for RA3 is the most significant cooperation so far. For the past 2 years rheumatologists on both sides of the Atlantic have been working on this project, and the fruits of their work are …