The criteria were first presented in a well organized, fast-paced, and densely packed session at the ACR Annual Scientific Meeting in October 2009. There, members of the ACR–EULAR task force premiered the results of the ambitious three-year collaborative effort to develop updated RA classification criteria. Their data- and consensus-driven process has yielded a new approach with an emphasis on identifying patients with a relatively short duration of symptoms who may benefit from early initiation of disease-modifying antirheumatic drug (DMARD) therapy or entry into clinical trials of promising new agents.
Why New Criteria?
This effort was undertaken to update the ACR RA classification criteria published in 1987. As noted by the authors, the 1987 criteria were derived by discriminating patients with established RA from those with other definite rheumatologic diagnoses; therefore, they are not helpful in identifying patients who would benefit from early intervention. Identifying RA at later stages is easy, remarked Paul Emery, MA, MD, professor of rheumatology and head of the academic section of MSK Disease at the Leeds Institute of Molecular Medicine at the University of Leeds, United Kingdom, in his 2009 ACR meeting presentation about the need for new RA criteria. The problem is that classification using the 1987 criteria only occurs after nodules and radiographic changes are apparent. Research in the intervening decades has established that RA is characterized by “an evolving phenotype, and this evolution can actually be interrupted,” he noted. This is the goal of newer RA therapies—preventing patients with RA from reaching a chronic, erosive disease state.
Having uniform criteria to classify patients with early disease facilitates clinical trials that investigate the efficacy of early interventions in preventing later-stage RA. “If our job as rheumatologists is to prevent disease,” Dr. Emery reminded his audience, “then early therapy is essential.”
Alan J. Silman, MD, from the Arthritis Research Campaign in Chesterfield, United Kingdom, and a member of the task force, summarized the history of RA classification criteria at the annual meeting session. The 1987 ACR Criteria, following earlier efforts such as the 1956 ARA criteria, 1961 Rome criteria, and 1966 New York criteria, was the first classification to use an analytical approach. The 1987 ACR Criteria “were not designed to work when we most need them,” he said. To address this need, a joint task force of the ACR and EULAR was formed and developed criteria in the phased approach described below. Importantly, the focus of this endeavor was not on developing diagnostic criteria or informing primary care referral.
Phase One: Data Analysis
As the task force began its work, said Dr. Silman, its assignment was to use available data to statistically develop rules that could best differentiate subgroups of patients with newly presenting, undifferentiated inflammatory synovitis at sufficiently high risk of persistent and/or erosive disease from those with lower risk. For ethical reasons, a natural history study would have been out of the question. “Nobody now waits for someone to develop erosive disease before they start DMARD therapy,” he noted.