Table 1 Patient characteristics
|  | Female (n = 11,916) | Male (n = 3042) | Δ25% trimmed mean (95% CI) |
|---|---|---|---|
Age, years | 68 (58–75) | 69 (62–76) |  − 1.8 (− 2.3 to − 1.3) |
Age at onset, years | 52 (41–62) | 59 (50–67) |  − 6.9 (− 7.5 to − 6.3) |
Disease duration, years | 11 (6–20) | 8 (4–14) | 3.6 (3.2 to 3.9) |
Number of artificial joints | 0 (Q1–Q3, 0–0; range, 0–9) | 0 (Q1–Q3, 0–0; range, 0–7) | 0.0 (0.0 to 0.0) |
Stage | |||
 I | 2752 (25.3) | 980 (35.6) | – |
 II | 2908 (26.8) | 928 (33.7) | – |
 III | 2094 (19.3) | 479 (17.4) | – |
 IV | 3103 (28.6) | 363 (13.2) | – |
 Missing data | 1059 | 292 | – |
Class | |||
 I | 3762 (34.6) | 1247 (45.0) | – |
 II | 4960 (45.6) | 1168 (42.2) | – |
 III | 1848 (17.0) | 306 (11.0) | – |
 IV | 314 (2.9) | 50 (1.8) | – |
 Missing data | 1032 | 271 | – |
BMI, kg/m2 | 21.92 (3.73) | 23.01 (3.38) |  − 1.29 (− 1.44 to − 1.15) |
 Missing data | 1722 | 422 |  |
Steroid | |||
 Regular use | 4110 (34.5) | 1137 (37.4) | – |
 Missing data | 0 | 1 | – |
NSAIDs | |||
 Regular use | 3609 (30.3) | 959 (31.5) | – |
 Missing data | 1 | 0 | – |
RF, IU/mL | 44.0 (14.0–121.0) | 45.0 (10.0–160.2) |  − 5.69 (− 11.27 to − 0.67) |
 Positive (> 15) | 6872 (73.7) | 1614 (68.6) | – |
 Missing data | 2598 | 690 | – |
Anti-CCP, U/mL | 52.9 (3.6–266.0) | 60.5 (0.7–338.5) |  − 16.00 (− 34.00 to 0.72) |
 Positive (≥ 4.5) | 2970 (74.1) | 806 (67.7) | – |
 Missing data | 7908 | 1851 | – |
HAQ-DI | 0.38 (0.00–1.00) | 0.00 (0.00–0.50) | 0.275 (0.249 to 0.301) |
 Missing data | 2991 | 777 | – |
Smoking status | |||
 Never | 7734 (79.1) | 625 (24.7) | – |
 Former | 1386 (14.2) | 1322 (52.3) | – |
 Current | 654 (6.7) | 583 (23.0) | – |
 Missing data | 2142 | 512 | – |
DAS28-ESR | 2.9 (2.2–3.7) | 2.5 (1.8–3.3) | 0.39 (0.33 to 0.45) |
 Remission | 3552 (40.7) | 1183 (53.9) | – |
 Low | 1857 (21.3) | 386 (17.6) | – |
 Moderate | 2891 (33.1) | 531 (24.2) | – |
 High | 428 (4.9) | 94 (4.3) | – |
 Missing data | 3188 | 848 | – |
DAS28-CRP | 2.1 (1.5–2.9) | 2.0 (1.5–2.8) | 0.09 (0.04 to 0.13) |
 Remission | 6868 (67.1) | 1815 (69.5) | – |
 Low | 1509 (14.7) | 362 (13.9) | – |
 Moderate | 1691 (16.5) | 387 (14.8) | – |
 High | 170 (1.7) | 46 (1.8) | – |
 Missing data | 1678 | 432 | – |
CDAI | 4.8 (1.9–9.2) | 3.7 (1.3–7.8) | 1.05 (0.82 to 1.29) |
 Remission | 3537 (34.7) | 1110 (42.6) | – |
 Low | 4483 (43.9) | 1060 (40.7) | – |
 Moderate | 1851 (18.1) | 363 (13.9) | – |
 High | 333 (3.3) | 72 (2.8) | – |
 Missing data | 1712 | 437 | – |
SDAI | 5.2 (2.1–9.9) | 4.2 (1.6–8.6) | 0.88 (0.62 to 1.12) |
 Remission | 3684 (36.2) | 1101 (42.3) | – |
 Low | 4388 (43.1) | 1053 (40.5) | – |
 Moderate | 1853 (18.2) | 382 (14.7) | – |
 High | 247 (2.4) | 64 (2.5) | – |
 Missing data | 1744 | 442 | – |