Patient characteristics at initiation of first TNF inhibitor between 2003 and 2011 in 9139 Swedish patients with rheumatoid arthritis*
| Etanercept (n=3892) | Adalimumab (n=2349) | Infliximab (n=2898) | p Value† | |
|---|---|---|---|---|
| Sex, n (%) | ||||
| Women | 2995 (77%) | 1766 (75%) | 2151 (74%) | 0.03 |
| Age (years) | ||||
| Mean (SD) | 55.1 (13.7) | 55.7 (13.3) | 56.7 (13.1) | <0.001 |
| Rheumatoid factor status, n (%) | ||||
| Positive | 496 (74%) | 267 (76%) | 389 (75%) | <0.001 |
| Negative | 2082 (18%) | 1301 (16%) | 1563 (18%) | |
| Unspecified | 281 (8.3%) | 146 (8.0%) | 132 (7.2%) | |
| HAQ, n (%) | ||||
| Mean (SD) | 1.15 (0.64) | 1.15 (0.65) | 1.20 (0.64) | 0.002 |
| <1.00 | 1334 (34%) | 811 (35%) | 895 (31%) | <0.001 |
| 1.00–1.49 | 1048 (27%) | 623 (27%) | 727 (25%) | |
| 1.5–1.99 | 656 (17%) | 419 (18%) | 536 (18%) | |
| ≥2.00 | 452 (12%) | 273 (12%) | 360 (12%) | |
| Missing | 402 (10%) | 223 (9.5%) | 380 (13%) | |
| DAS28, n (%) | ||||
| Mean (SD) | 5.1 (1.4) | 5.1 (1.4) | 5.2 (1.4) | 0.004 |
| <3.2 | 318 (8.2%) | 176 (7.5%) | 207 (7.1%) | <0.01 |
| 3.2–5.1 | 1371 (35%) | 832 (35%) | 935 (32%) | |
| ≥5.2 | 1617 (42%) | 1019 (43%) | 1276 (44%) | |
| Missing | 586 (15%) | 322 (14%) | 480 (17%) | |
| Disease duration (years), n (%) | ||||
| Mean (SD) | 12 (14) | 13 (16) | 13 (17) | <0.01 |
| Median (p25–75) | 7 (3–16) | 8 (3–17) | 8 (3–16) | |
| <1 year | 259 (6.7%) | 143 (6.1%) | 251 (8.7%) | 0.002 |
| 1–4.9 year | 1218 (31%) | 681 (29%) | 870 (30%) | |
| 5–9.9 year | 794 (20%) | 468 (20%) | 559 (19%) | |
| ≥10 | 1579 (41%) | 1022 (44%) | 1187 (41%) | |
| Missing | 113 (1.1%) | 35 (1.5%) | 31 (1.1%) | |
| TNF inhibitors, n (%) | ||||
| 2003–2005 | 1240 (39%) | 852 (27%) | 1076 (34%) | <0.001 |
| 2006–2009 | 1915 (46%) | 1041 (25%) | 1228 (29%) | |
| 2010–2011 | 737 (41%) | 456 (26%) | 594 (33%) | |
| Concomitant DMARDs, n (%) | ||||
| No | 1072 (28%) | 561 (24%) | 335 (12%) | <0.001 |
| MTX | 2267 (58%) | 1443 (61%) | 2162 (75%) | |
| Other | 553 (14%) | 345 (15%) | 401 (14%) | |
| Hospital days‡ | ||||
| Mean (SD) | 4 (13) | 4 (11) | 5 (14) | 0.002 |
| Median (p25–75) | 0 (0–3) | 0 (0–3) | 0 (0–4) | |
| Outpatient visits‡ | ||||
| Mean (SD) | 11 (9) | 9 (8) | 10 (8) | <0.001 |
| Median (p25–75) | 9 (5–15) | 7 (4–13) | 8 (4–13) | |
*p25–75=25th to 75th centile.
†Calculated using ANOVA with Bonferroni correction.
‡Assessed during the 2 years preceding TNFi treatment initiation. Data on hospital days and non-primary outpatient care visits retrieved from the Swedish National Patient Register between 2001 and 2009, and include admissions and visits due to any cause.
ACR, American College of Rheumatology; ANOVA, analysis of variance; DAS28, disease activity score 28 joint count; DMARD, disease modifying antirheumatic drug; HAQ, health assessment questionnaire; MTX, methotrexate; TNF, tumour necrosis factor; TNFi, TNF inhibitor.