Table 1 Demographic features of patients on each observation year
| Â | Registration | 1st year | 2nd year | 3rd year | 4th year |
|---|---|---|---|---|---|
Patients (n) | 1127 | 1127 | 997 | 808 | 588 |
Age (years) | Â | Â | Â | Â | Â |
 Mean ± SD | 68.2 ± 10.2 | 69.2 ± 11.1 | 70.0 ± 10.2 | 70.7 ± 9.8 | 71.0 ± 9.4 |
 Median, IQR | 69, 62–76 | 70, 63–77 | 71, 64–77 | 71, 65–78 | 71, 65–78 |
Sex, female (%) | 799 (70.9) | 799 (70.9) | 714 (71.6) | 595 (73.6) | 441 (75.0) |
Disease duration (months) | Â | Â | Â | Â | Â |
 Mean ± SD | 123.4 ± 115.1 | 135.5 ± 115.5 | 147.7 ± 114.5 | 163.6 ± 114.1 | 177.3 ± 112.0 |
 Median, IQR | 93, 36–169 | 105, 48–181 | 117, 61–193 | 112, 80–207 | 147, 97–218 |
DAS28 score (average, SD) | 3.18 ± 1.76 | 2.88 ± 1.58 | 2.92 ± 1.57 | 2.84 ± 1.52 | 2.83 ± 1.53 |
Change of prescription | Â | 456 (40.5) | 360 (36.1) | 282 (34.9) | 191 (32.5) |
Prednisolone | |||||
 Number of patients (%) | 476 (42.2) | 435 (38.6) | 352 (35.3) | 280 (34.7) | 166 (28.2) |
 Average dose (mg/day) |  |  |  |  |  |
  Mean ± SD | 4.22 ± 2.54 | 4.25 ± 2.94 | 4.21 ± 2.77 | 4.13 ± 2.92 | 3.99 ± 2.83 |
  ≥ 5 mg, number (%) | 243 (21.6) | 204(18.1) | 165 (16.5) | 118 (14.6) | 68 (11.5) |
Biologic DMARDs | |||||
 Number of patients (%) | 302 (26.7) | 314(27.8) | 282 (28.2) | 244 (30.2) | 199 (33.8) |
 Etanercept, number (%) | 115 (10.2) | 119 (10.6) | 105 (10.5) | 88 (10.9) | 77 (13.1) |
 Infliximab, number (%) | 34 (3.0) | 30 (2.7) | 24 (2.4) | 22 (2.7) | 12 (2.0) |
 Adalimumab, number (%) | 35 (3.1) | 28 (2.5) | 25 (2.5) | 18 (2.2) | 14 (2.4) |
 Tocilizumab, number (%) | 53 (4.7) | 61 (5.4) | 59 (5.9) | 58 (7.2) | 51 (8.7) |
 Abatacept, number (%) | 28 (2.5) | 34 (3.0) | 40 (4.0) | 34 (4.2) | 31 (5.3) |
 Golimumab, number (%) | 33 (2.9) | 39 (3.5) | 32 (3.2) | 26 (3.2) | 13 (2.2) |
 Others, number (%) | 4 (0.4) | 3 (0.3) | 13 (1.3) | 13 (1.6) | 9 (1.5) |
Methotrexate | |||||
 Number of patients (%) | 886 (78.6) | 835 (74.1) | 731 (73.3) | 581 (71.9) | 414 (70.4) |
 Average dose (mg/week), mean ± SD | 7.51 ± 3.83 | 7.49 ± 4.01 | 7.31 ± 3.96 | 7.20 ± 3.92 | 7.00 ± 3.84 |
Other immunosuppressive drugs | |||||
 Number of patients (%) | 182 (16.1) | 191 (16.9) | 168 (16.8) | 140 (17.3) | 117 (19.8) |
 Tacrolimus, number (%) | 139 (12.3) | 160 (14.2) | 137 (13.7) | 114 (14.1) | 96 (16.3) |
 Mizoribine, number (%) | 32 (2.8) | 32 (2.8) | 29 (2.9) | 24 (3.0) | 19 (3.2) |
 Leflunomide, number (%) | 6 (0.5) | 6 (0.5) | 7 (0.7) | 6 (0.7) | 6 (1.0) |
 Others, number (%) | 5 (0.5) | 3 (0.3) | 2 (0.2) | 3 (0.4) | 3 (0.5) |