EULAR Criteria for Rheumatoid Arthritis
Classification Criteria for Diagnosis
The 2010 ACR/EULAR classification criteria require a score of ≥6 out of 10 points across four domains to definitively classify rheumatoid arthritis, and these criteria are designed for early identification of patients at risk for persistent and erosive disease. 1, 2
Scoring System
The classification system uses four domains 1, 2:
Joint Involvement:
- 1 large joint = 0 points
- 2-10 large joints = 1 point
- 1-3 small joints (with or without large joints) = 2 points
- 4-10 small joints (with or without large joints) = 3 points
Serology:
- Negative RF and negative ACPA = 0 points
- Low-positive RF or low-positive ACPA (≤3× upper limit of normal) = 2 points
- High-positive RF or high-positive ACPA (>3× upper limit of normal) = 3 points 1, 2, 3
Acute Phase Reactants:
Duration of Symptoms:
Prerequisites for Application
The criteria apply only to patients who have 1, 2:
- At least one joint with definite clinical synovitis (swelling)
- Synovitis not better explained by another disease
Important caveat: Patients with erosive disease typical of RA with compatible history should be classified as having RA regardless of their score, and patients with longstanding disease who previously met criteria should continue to be classified as having RA. 1
Performance Characteristics
The 2010 criteria demonstrate higher sensitivity (0.82-0.91) but lower specificity (0.48-0.65) compared to the 1987 ACR criteria, meaning they capture more early RA cases but may include some patients who won't develop persistent disease. 4, 5 The criteria perform particularly well when validated against methotrexate initiation (sensitivity 0.85, specificity 0.52) and expert diagnosis (sensitivity 0.88, specificity 0.48). 5
Clinical pitfall: The 2010 criteria may over-classify older patients (≥60 years) as having RA, so clinical judgment remains essential. 4 Additionally, 20-30% of RA patients are seronegative, so negative RF does not exclude the diagnosis. 2
EULAR Treatment Recommendations
Core Treatment Principles
EULAR recommends that treatment begin immediately after RA diagnosis with methotrexate as the anchor drug, targeting sustained remission or low disease activity, with frequent monitoring every 1-3 months and mandatory treatment adjustment if no improvement occurs by 3 months or target is not reached by 6 months. 6, 1
Treatment Algorithm
Phase I: Initial Treatment 6
- Start methotrexate at optimal dose (25-30 mg weekly with folate supplementation), recognizing maximal effect requires 4-6 months 6
- Combine with short-term low-dose glucocorticoids that should be tapered as rapidly as clinically feasible 6, 1
- Alternative if methotrexate contraindicated: Start leflunomide or sulfasalazine 6, 1
- Assess at 3 months: If no improvement, adjust therapy immediately 6
- Assess at 6 months: If target not achieved, move to Phase II 6
Phase II: Treatment Escalation 6
The decision pathway depends on prognostic factors:
If unfavorable prognostic factors present (very high disease activity, early joint damage, high-positive RF/ACPA):
- Add a biologic agent: TNF-inhibitor (adalimumab, certolizumab, etanercept, golimumab, infliximab or biosimilars), OR abatacept, OR tocilizumab 6
If unfavorable prognostic factors absent:
Add or switch conventional synthetic DMARDs: Consider combinations of methotrexate with sulfasalazine and/or hydroxychloroquine (triple therapy) 6
Reassess at 6 months: If target achieved, continue; if not, proceed to Phase III 6
Phase III: Biologic Switching 6
- Replace first biologic with another biologic with different mechanism of action: Switch between TNF-inhibitors, abatacept, rituximab, or tocilizumab 6
- After two biologic failures: Consider JAK inhibitor (tofacitinib) plus conventional DMARD, though efficacy after multiple biologic failures is less well-studied 6
Treatment Targets and Monitoring
Primary target: Clinical remission according to ACR/EULAR definition 6, 1
Alternative target: Low disease activity (when remission unlikely to be achievable, particularly in longstanding disease) 6
Remission definitions: 7
- Boolean 2.0 criteria (revised 2022): Tender joint count ≤1, swollen joint count ≤1, CRP ≤1 mg/dL, and patient global assessment ≤2 cm (on 0-10 scale)
- SDAI remission: ≤3.3
- CDAI remission: Similar threshold
Critical note: DAS28 <2.6 is NOT considered sufficiently stringent for true remission. 1 The ACR/EULAR remission definitions are preferred and predict better radiographic and functional outcomes. 7
- Every 1-3 months with active disease
- Every 6-12 months once treatment target stabilized
- Use composite measures (DAS28, SDAI, or CDAI) to guide decisions
Difficult-to-Treat RA Definition
EULAR defines difficult-to-treat RA as requiring ALL of the following 1, 2:
- Treatment failure of ≥2 biologic or targeted synthetic DMARDs with different mechanisms of action after failing conventional synthetic DMARD therapy
- Signs of active or progressive disease
- Management perceived as problematic by rheumatologist and/or patient
Key Clinical Pitfalls
Do not delay treatment waiting for positive serology – seronegative RA accounts for 20-30% of cases and has similar prognosis to seropositive disease. 2
Do not dismiss diagnosis based on normal ESR/CRP – acute phase reactants can be normal even in active disease and are poor predictors of RA. 2
Do not maintain suboptimal methotrexate dosing – the optimal dose (25-30 mg weekly) should be reached within a few weeks and maintained for at least 8 weeks, with recognition that maximal efficacy may not appear until 4-6 months. 6
Do not wait beyond 3 months without improvement – therapy must be adjusted if no improvement is seen by 3 months, even if the 6-month target assessment hasn't arrived. 6
Do not use DAS28 <2.6 as remission target – this threshold is not sufficiently stringent; use ACR/EULAR Boolean or index-based remission criteria instead. 1