| Characteristics | Patients with ERA(n = 100) | LSRA(n = 114) |
| Female, n (%) | 75 (75.0) | 97 (85.1) |
| Age (years), mean (SD) | 54.9 (13.8) | 57.1 (13.6) |
| Disease duration (years), mean (SD) | 0.6 (0.3) | 13.7 (10.0) |
| Tender joint count, mean (SD) | 15.5 (10.1) | 8.3 (8.9) |
| Swollen joint count, mean (SD) | 11.4 (8.7) | 5.3 (6.2) |
| Anti-CCP (U/ml), mean (SD) {median} | 48.6 (63.4) {13.9} | 49.6 (91.3) {17.0} |
| Anti-CCP ⩾5 U/ml, n (%) | 65 (65.0) | 78 (68.4) |
| IgM RF (U/ml), mean (SD) {median} | 61.6 (98.6) {27.1} | 46.5 (78.8) {13.4} |
| IgM RF ⩾20 U/ml, n (%) | 54 (54.0) | 47 (41.2) |
| IgA RF (U/ml), mean (SD) {median} | 75.6 (149.9) {14.8} | 52.0 (122.2) {10.2} |
| IgA RF ⩾20 U/ml, n (%) | 43 (43.0) | 33 (28.9) |
| CRP (mg/l), mean (SD) | 24.1 (30.6) | 6.9 (11.9) |
| ESR (mm/1st h), mean (SD) | 40.6 (24.6) | 23.7 (19.5) |
| DAS44, mean (SD) | 3.9 (1.4) | 2.7 (1.4) |
| HAQ, mean (SD) | 1.24 (0.78) | 1.05 (0.80) |
anti-CCP, anti-cyclic citrullinated protein; CRP, C-reactive protein; DAS, disease activity score; ERA, early rheumatoid arthritis; ESR, erythrocyte sedimentation rate; HAQ, Health Assessment Questionnaire; LSRA, longstanding rheumatoid arthritis; RF, rheumatoid factor.