Table 1. Baseline clinical and demographic characteristics.
| All RA patients | Seropositive RA patients | Seronegative RA patients | |
| No. | 538 (−) | 407 (75.7%) | 131 (24.3%) |
| Female | 407 (75.7%) | 303 (74.4%) | 105 (80.2%) |
| Age/years (SD) | |||
| at treatment start | 55.0 (13.0) | 55.7 (12.8) | 53.0 (13.6) |
| Smoking status | |||
| Current | 142 (31.8%) | 110 (32.7%) | 32 (29.1%) |
| Previous | 151 (33.9%) | 120 (35.7%) | 31 (28.2%) |
| Never | 153 (34.3%) | 106 (31.6%) | 47 (42.7%) |
| Missing data | 92 (−) | 71 (−) | 21 (−) |
| DMARD | 453 (84.2%) | 343 (84.3%) | 110 (84.0%) |
| VAS Patient global score (0–100)/Mean (SD) | 62.6 (22.6) | 60.8 (22.9) | 68.5 (20.7) |
| VAS Physician global score (0–100)/Mean (SD) | 38.4 (20.7) | 38.0 (20.2) | 39.8 (22.3) |
| VAS pain score (0–100)/Mean (SD) | 58.0 (22.8) | 55.9 (23.2) | 64.4 (20.2) |
| TJC 0-28/Mean (SD) | 9.5 (7.3) | 9.0 (7.0) | 11.1 (8.1) |
| SJC 0-28/Mean (SD) | 5.4 (4.6) | 5.6 (4.5) | 4.8 (4.8) |
| HAQ score/Mean (SD) | 1.2 (0.7) | 1.2 (0.7) | 1.3 (0.7) |
| CRP/mg/mL (SD) | 19.7 (25.5) | 20.5 (27.0) | 17.2 (20.3) |
| DAS28/mean (SD) | 4.9 (1.2) | 4.8 (1.2) | 5.0 (1.1) |
| Anti-TNF drug | |||
| Infliximab (%) | 168 (31.2%) | 122 (30.0%) | 46 (35.1%) |
| Etanercept (%) | 166 (30.8%) | 124 (30.5%) | 42 (32.1%) |
| Adalimumab (%) | 134 (24.9%) | 105 (25.8%) | 29 (22.1%) |
| Golimumab (%) | 49 (9.1%) | 38 (9.3%) | 11 (8.4%) |
| Certolizumab (%) | 21 (3.9%) | 18 (4.4%) | 3 (2.3%) |
| EULAR response | |||
| Good (%) | 231 (42.9%) | 178 (43.7%) | 53 (40.5%) |
| Moderate (%) | 148 (27.5%) | 108 (26.5%) | 40 (30.5%) |
| None (%) | 159 (29.6%) | 121 (29.7%) | 38 (29.0%) |
| ACR50 response (%) | 170 (31.6%) | 131 (32.2%) | 39 (29.8%) |
| RelDAS28 response (SD) | 0.28 (0.32) | 0.28 (0.34) | 0.285 (0.27) |
SD: standard deviation, DMARD: disease modifying anti-rheumatic drugs, VAS: visual analogue scale, TJC: tender joint count, SJC: swollen joint count, HAQ: health assessment score, CRP: C-reactive protein, DAS28: disease activity score (28-joints), EULAR: European League Against Rheumatism, ACR50: American College of Rheumatology, 50% improvement, RelDAS28: relative change in DAS28.