Table 1. Baseline RA Cohort Characteristics and Covariates by Drug Class.
| Variable | Patients, No. (%) | ||||
|---|---|---|---|---|---|
| TNFi (n = 20 586 [74%]) | Rituximab (n = 1182 [4%]) | IL-6i (n = 1068 [4%]) | Abatacept (n = 2255 [8%]) | JAKi (n = 2570 [9%]) | |
| Demographic characteristics | |||||
| Age, median (IQR), y | 50 (41-55) | 50 (41-55) | 50 (42-56) | 50 (43-56) | 50 (43-56) |
| Sex | |||||
| Female | 16 057 (78) | 942 (80) | 839 (79) | 1904 (84) | 2077 (81) |
| Male | 4529 (22) | 240 (20) | 229 (21) | 351 (16) | 493 (19) |
| Geographic region | |||||
| Northeast | 2723 (13) | 201 (17) | 147 (14) | 314 (14) | 395 (15) |
| North Central | 4212 (20) | 244 (21) | 215 (20) | 437 (19) | 474 (18) |
| South | 10 244 (50) | 522 (44) | 505 (47) | 1130 (50) | 1314 (51) |
| West | 3118 (15) | 201 (17) | 187 (18) | 346 (15) | 375 (15) |
| Unknown | 289 (1) | 14 (1) | 14 (1) | 28 (1) | 12 (1) |
| Year of treatment exposure, median (IQR) | 2016 (2014-2018) | 2016 (2014-2018) | 2016 (2014-2018) | 2016 (2014-2018) | 2019 (2016-2020) |
| Proxies of RA severity | |||||
| Fills of glucocorticoids in 3 mo prior | 9573 (47) | 539 (46) | 481 (45) | 978 (43) | 1091 (42) |
| Fills of conventional synthetic DMARD in 3 mo prior | 14 825 (72) | 536 (45) | 540 (51) | 1383 (61) | 1703 (66) |
| Clinical characteristics | |||||
| Time from RA diagnosis to treatment exposure, median (IQR), d | 470 (240-970) | 680 (350-1310) | 680 (380-1200) | 640 (370-1210) | 720 (400-1330) |
| Tobacco use | 1555 (8) | 97 (8) | 76 (7) | 169 (7) | 176 (7) |
| Frailty score, median (IQR)a | 0.13 (0.12-0.16) | 0.14 (0.12-0.18) | 0.14 (0.12-0.16) | 0.14 (0.12-0.16) | 0.13 (0.12-0.16) |
| Charlson comorbidity score | |||||
| 1-2 | 18 157 (88) | 897 (76) | 887 (83) | 1880 (83) | 2258 (88) |
| 3-4 | 1949 (9) | 213 (18) | 133 (12) | 286 (13) | 243 (9) |
| ≥5 | 480 (2) | 72 (6) | 48 (4) | 89 (4) | 69 (3) |
| Health care utilization in 12 mo prior | |||||
| ≥1 Hospital admission | 1678 (8) | 249 (21) | 120 (11) | 223 (10) | 201 (8) |
| ≥1 Emergency department visit | 5408 (26) | 458 (38) | 340 (32) | 671 (30) | 609 (24) |
| ≥1 Outpatient visit | 20 574 (100) | 1182 (100) | 1068 (100) | 2255 (100) | 2567 (100) |
| ≥1 Opioid prescription fill | 8042 (39) | 443 (37) | 424 (40) | 919 (41) | 877 (34) |
| ≥1 NSAID prescription fill | 11 496 (56) | 419 (35) | 508 (48) | 1156 (51) | 1440 (56) |
| Reason for end of follow-up | |||||
| Enrollment ended | 8030 (39) | 247 (21) | 341 (32) | 842 (37) | 1057 (41) |
| Did not refill in 90 of 180 d | 10 278 (50) | 913 (77) | 474 (44) | 869 (39) | 1122 (44) |
| Switched to allowed drug category | 2114 (10) | 4 (0.3) | 109 (10) | 222 (10) | 0 |
| Switched to not allowed drug category | 0 | 4 (0.3) | 136 (13) | 292 (13) | 369 (14) |
| Filled >1 drug category on same day | 2 (0.01) | 0 | 0 | 0 | 0 |
| Cancer outcome | 162 (1) | 14 (1) | 8 (1) | 30 (1) | 22 (1) |
| Follow-up, median (IQR), d | 300 (180-550) | 190 (180-240) | 230 (150-410) | 260 (170-520) | 270 (170-450) |
Abbreviations: DMARD, disease-modifying antirheumatic drug; IL-6i, interleukin-6 inhibitor; JAKi, Janus kinase inhibitor; NSAID, nonsteroidal anti-inflammatory drug; RA, rheumatoid arthritis; TNFi, tumor necrosis factor inhibitor.
a
Frailty score: range, 0 (not at all frail) to 1 (severely frail).