Groups | Total number | IR (95% CI) | Adjusted IR (95% CI)a | ||||||
---|---|---|---|---|---|---|---|---|---|
<1 year | 1–5 years | ≥5 years | <1 year | 1–5 years | ≥5 years | <1 year | 1–5 years | ≥5 years | |
Overall (n=7645) | |||||||||
 Overall | 1359 | 4173 | 2113 | 13.06 (12.38, 13.77) | 8.21 (7.97, 8.46) | 2.70 (2.59, 2.82) | - | - | - |
 FIT (-) group (Ref.) | 1038 | 3113 | 1583 | 12.78 (12.03, 13.59) | 7.87 (7.59, 8.15) | 2.62 (2.50, 2.75) | 11.89 (10.56, 13.38) | 7.56 (6.85, 8.33) | 2.60 (2.37, 2.86) |
 FIT (+) Group | 321 | 1060 | 530 | 14.02 (12.57, 15.64) | 9.43 (8.88, 10.01) | 2.97 (2.72, 3.23) | 13.27 (11.79, 14.93) | 8.88 (8.06, 9.80) | 2.92 (2.65, 3.21) |
 p value |  |  |  | 0.948 | 0.898 | 0.931 | 0.196 | 0.022 | 0.094 |
Seropositive RA (n=3184) | |||||||||
 Overall | 553 | 1715 | 916 | 5.31 (4.89, 5.77) | 3.37 (3.21, 3.53) | 1.17 (1.09, 1.24) | - | - | - |
 FIT (−) group (Ref.) | 428 | 1287 | 698 | 5.27 (4.80, 5.80) | 3.25 (3.07, 3.43) | 1.15 (1.07, 1.24) | 4.94 (3.77, 6.47) | 3.16 (2.84, 3.52) | 1.15 (1.06, 1.25) |
 FIT (+) Group | 125 | 428 | 218 | 5.46 (4.58, 6.51) | 3.80 (3.45, 4.18) | 1.21 (1.06, 1.39) | 5.44 (4.15, 7.13) | 3.64 (3.27, 4.06) | 1.20 (1.10, 1.31) |
 p value |  |  |  | 0.980 | 0.912 | 0.970 | 0.622 | 0.069 | 0.457 |
Seronegative RA (n=4461) | |||||||||
 Overall | 806 | 2458 | 1197 | 7.74 (7.23, 8.30) | 4.83 (4.64, 5.03) | 1.53 (1.44, 1.61) | - | - | - |
 FIT (−) group (Ref.) | 610 | 1826 | 885 | 7.51 (6.94, 8.13) | 4.61 (4.40, 4.82) | 1.46 (1.37, 1.56) | 7.04 (6.01, 8.26) | 4.39 (3.91, 4.93) | 1.45 (1.27, 1.65) |
 FIT (+) Group | 196 | 632 | 312 | 8.56 (7.44, 9.85) | 5.61 (5.19, 6.07) | 1.74 (1.56, 1.95) | 7.51 (6.40, 8.80) | 5.19 (4.62, 5.83) | 1.70 (1.49, 1.93) |
 p value |  |  |  | 0.927 | 0.889 | 0.902 | 0.581 | 0.046 | 0.087 |