Baseline characteristics of the study patients (the per-protocol population)
| Group 1 (n=54) | Group 2 (n=44) | Group 3 (n=49) | Group 4 (n=52) | p Value | |
| Female | 45 (83.3) | 39 (88.6) | 42 (85.7) | 43 (82.7) | 0.854 |
| Age, years | 59.1±13.1 | 58.5±113.3 | 58.1±10.9 | 58.1±11.7 | 0.854 |
| Body mass index, kg/m2 | 22.5±3.0 | 22.6±3.7 | 23.1±3.7 | 23.4±3.2 | 0.418 |
| Duration of RA, years | 5.2±4.5 | 6.1±4.9 | 4.9±4.4 | 6.2±5.5 | 0.429 |
| RF positivity | 41/52 (78.8) | 37/43 (86.0) | 39/49 (79.6) | 41/51 (80.4) | 0.824 |
| Anti-CCP positivity | 37/46 (80.4) | 31/35 (88.6) | 39/46 (84.8) | 32/36 (88.9) | 0.675 |
| DAS28-CRP | 2.5±1.1 | 2.8±1.2 | 2.6±1.0 | 2.6±1.0 | 0.604 |
| Treatment | |||||
| GC | 25 (46.3) | 29 (65.9) | 32 (65.3) | 29 (55.8) | 0.152 |
| GC dose, mg/day | 2.2±2.8 | 3.0±2.5 | 2.9±2.4 | 2.4±2.3 | 0.320 |
| MTX dose, mg/week | 12.7±3.7 | 13.3±3.4 | 13.6±2.9 | 13.2±3.3 | 0.603 |
| Sulfasalazine | 5 (9.3) | 3 (6.8) | 5 (10.2) | 6 (11.5) | 0.878 |
| HCQ | 10 (18.5) | 5 (11.4) | 8 (16.3) | 5 (9.3) | 0.540 |
| Leflunomide | 14 (25.9) | 8 (18.2) | 8 (16.3) | 16 (30.8) | 0.288 |
| Biological DMARDs | |||||
| TNF inhibitor | 5 (9.3) | 4 (9.1) | 6 (12.2) | 4 (7.7) | 0.888 |
| Abatacept | 0 (0) | 2 (4.5) | 0 (0) | 1 (1.9) | 0.135 |
| Tocilizumab | 0 (0 | 2 (4.5) | 3 (6.1) | 2 (3.8) | 0.329 |
| Rituximab | 0 (0) | 0 (0) | 0 (0) | 1 (1.9) | 0.729 |
| Tofacitinib | 0 (0) | 0 (0) | 1 (2.0) | 0 (0) | 0.467 |
| Seroprotection | |||||
| H1N1 | 18 (33.3) | 20 (45.5) | 20 (40.8) | 19 (36.5) | 0.638 |
| H3N2 | 39 (72.2) | 23 (52.3) | 26 (53.1) | 28 (53.8) | 0.115 |
| B-Yamagata | 21 (38.9) | 14 (31.8) | 19 (38.8) | 11 (21.2) | 0.117 |
The data are expressed as absolute number (frequency) or mean±SD.
p Values were determined by using t test, Mann-Whitney U test, χ2 test or Fisher’s exact test, as appropriate.
Anti-CCP, anti-cyclic citrullinated peptide; CRP, C reactive protein; DAS28, Disease Activity Score in 28 joints; DMARDs, disease-modifying antirheumatic drugs; ESR, erythrocyte sedimentation rate; GC, glucocorticoids; HCQ, hydroxychloroquine; LEF, leflunomide; MTX, methotrexate; RA, rheumatoid arthritis; RF, rheumatoid factor.