Background The 2010 ACR/EULAR classification criteria for rheumatoid arthritis (RA) have been developed to facilitate early recognition of and to guide therapeutic decisions in RA. Moreover, they are intended increase classification sensitivity and specificity, in particular in early arthritis . We tested performance of the new criteria in a cohort of very early arthritis patients who were enrolled in the ``Stop Arthritis Very Early`` (SAVE) clinical trial .
Objectives To investigate performance of the 2010 ACR/EULAR RA criteria in patients with ≤16 weeks duration of arthritis. This cohort represents a sample of patients presenting with early clinical arthritis and includes a variety of diseases diagnosed during follow-up.
Methods Baseline data from the 303 patients in the SAVE trial who had 12-months follow up were retrospectively scored according to the guidelines for application of the 2010 ACR/EULAR classification criteria. Outcome of this scoring (a score of 6 or greater classifying RA) was compared to two “gold standards” (endpoints): i) diagnosis according to the clinician (defined as a investigators’ diagnosis during or at the end of 12 months); ii) start of disease-modifying (DMARD) treatment within 12 months. Sensitivity, specificity, negative and positive predictive values with respect to the endpoints were calculated. In addition, receiver operating curves (ROC) were constructed for both endpoints
Results Predictive values, specificity/sensitivity as well as the area under the ROC curve are shown in the table. The ROC also demonstrated a score of 6 as the optimal cutpoint (with the highest sensitivity/specificity) for prediction of diagnosis and DMARD start.
“Misclassification” by the new criteria with respect to clinical diagnosis was observed in 80 patients: 58 (19.1%) were “false positive” and 22 (7.3%) “false negative”. The baseline clinical characteristics of false positives showed polyarticular (>10 joints) involvement (93.1%); abnormal acute phase reactants (77.6%), and long (>6 weeks) symptom duration (67.2%).
Conclusions In patients with very early arthritis, predictive and discriminative abilities of the 2010 ACR/EULAR classification criteria were satisfactory. Misclassification (especially “overclassification”) was frequent in patients with polyarticular involvement and either abnormal levels of acute phase reactants or a tendency to chronic course of the disease (symptoms duration ≥6 weeks).
Acknowledgement: This research was conducted while Iuliia Biliavska was an ARTICULUM Fellow.
Aletaha D, Neogi T, Silman AJ et al. 2010 Rheumatoid arthritis classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative. Arthritis Rheum 2010;62:2569-2581.
Machold KP, Landewe R, Smolen JS et al. The Stop Arthritis Very Early (SAVE) trial, an international multicentre, randomised, double-blind, placebo-controlled trial on glucocorticoids in very early arthritis. Ann Rheum Dis 2010;69:495-502.
Disclosure of Interest None Declared