The new ACR/EULAR classification criteria for RA: how are the new criteria performing in the clinic?

The objective of the 2010 ACR/European League Against Rheumatism classification criteria for RA was to distinguish patients at high risk for developing persistent erosive and/or inflammatory disease from those with undifferentiated inflammatory arthritis. These criteria were developed for use in clinical trials; in order to implement these criteria most effectively, they need to be validated in real-world settings. The 1987 criteria may have led to underdiagnosis in the case of patients with positive anti-citrullinated peptide antibody values but no evidence of radiographic progression of joint erosion, or overdiagnosis in the case of some patients with FM; similarly, the possibility that the 2010 criteria may result in overdiagnosis cannot be excluded. Prospective validation of the 2010 criteria has been carried out in several cohorts, with reported sensitivities ranging from 0.50 to 0.60 and specificities from 0.88 to 0.97. The sensitivity and specificity of the 2010 criteria were 0.74 and 0.66 when compared against the gold standard of needing MTX therapy in the opinion of experienced clinicians, and 0.69 and 0.72 against the standard of having persistent synovitis despite DMARDs after 1 year. Other comparisons have yielded similar sensitivities and specificities, ranging up to 0.85 for the gold standard of needing MTX therapy. Questions remain concerning the utility of the 2010 criteria for non-arthritis health care practitioners, who may be less than expert in identifying swollen joints and may underestimate the number of joints affected by synovitis. US may be of value in the future, but its role remains to be validated.