Background: The American College of Rheumatology (ACR) 1987 revised criteria for classification of rheumatoid arthritis (RA) are widely used for diagnosis. Objective: To evaluate the ability of the ACR set of criteria (both list and tree format) to diagnose RA compared to expert opinion according to disease duration.
Methods: A systematic literature review was conducted in Pubmed and Embase databases. All articles reporting the prevalence of RA according to ACR criteria and expert opinion in cohorts of early (< 1 year duration) or established (>1 year) arthritis were analyzed to calculate the sensitivity and specificity of ACR 1987 criteria against the gold standard (expert opinion). A meta-analysis using S-ROC curve was performed and pooled sensitivity and specificity were calculated with confidence intervals.
Results: Among the 138 publications initially identified, 19 were analysable (total:7438 patients, 3883 RA). In early arthritis, pooled sensitivity and specificity of ACR set of criteria were 77% (68-84%) and 77% (68-84%) in the list format versus 80% (72-88%) and 33% (24-43%) in the tree format. In established arthritis, sensitivity and specificity were respectively of 79% (71-85%) and 90% (84-94%) versus 80% (71-85%) and 93% (86-97%). The S-ROC meta-analysis confirmed the statistically significant differences suggesting that diagnostic performances of ACR list criteria are better in established arthritis.
Conclusion: This study indicates that specificity of ACR 1987 criteria in early RA is low, and that these criteria should not be used as diagnostic tools. However, sensitivity and specificity in established RA are higher, which reflects their use as classification criteria gold standard.