Patients with RA initiating TNF inhibitors as the first ever biological DMARD
| Source cohort | Sweden | Denmark | Norway | ||||||
| EIRA | SRQ | SRQ biobank | DANBIO | DRB | NOR-DMARD | ULRABIT | NOR-VEAC | ARCTIC | |
| N patients | 1628 | 22 486 | 2674 | 9312 | 2127 | 2036 | 141 | 96 | 52 |
| Characteristics at treatment start | |||||||||
| N women (%) | 1242 (76%) | 16 970 (75%) | 2060 (77%) | 6913 (74%) | 1601 (75%) | 1463 (72%) | 112 (79%) | 58 (60%) | 35 (67%) |
| Median age at baseline (IQR) | 55 (43,63) | 57 (46,65) | 56 (45,64) | 57 (48, 66) | 55 (46, 63) | 55 (44,63) | 53 (41,62) | 52 (40,63) | 53 (42,61) |
| Median calendar year of baseline (IQR) | 2010 (2006, 2015) | 2010 (2005, 2016) | 2013 (2011, 2016) | 2011 (2007, 2017) | 2011 (2007, 2016) | 2010 (2005, 2014) | 2011 (2010, 2012) | 2014 (2013, 2015) | 2012 (2012, 2013) |
| Median disease duration (IQR) | 2 (0,7)* | 3 (1,7)* | 3 (0,7)* | 5 (1, 12) | 5 (1, 12) | 5 (2,13) | 7 (3,13) | 1 (1,2) | 1 (1,2) |
| Seropositive disease† (%) | 1256 (78%) | 16 563 (77%) | 1922 (73%) | 7140 (80%) | 1661 (81%) | 1622 (80%) | 72 (76%) | 81 (84%) | 45 (87%) |
| Current smoker (%) | 361 (24%) | 2651 (14%) | 340 (13%) | 915 (26%) | 214 (25%) | 401 (23%) | 19 (21%) | 19 (21%) | 11 (21%) |
| Co-treatment with oral steroids (%) | 707 (43%) | 9821 (44%) | 1145 (43%) | 2376 (26%) | 496 (23%) | 966 (50%) | 65 (46%) | 40 (42%) | 20 (38%) |
| Visit-based clinical data | |||||||||
| Treatment start | |||||||||
| Median SJC(28) (IQR) | 6 (3–10) | 6 (3–10) | 5 (2–8) | 4 (2– 8) | 4 (2– 8) | 5 (2–9) | 4 (2–8) | 1 (0–3) | 0 (0–3) |
| Median TJC(28) (IQR) | 6 (3–10) | 6 (3–10) | 6 (3–10) | 6 (3– 12) | 6 (3– 11) | 5 (2–11) | 3 (1–7) | 1 (0–3) | 2 (0–6) |
| Median CRP (IQR) | 9 (4–21) | 10 (4–28) | 8 (3–20) | 11 (4– 25) | 10 (4– 24) | 8 (3–22) | 5 (2–13) | 3 (1–6) | 3 (1–6) |
| Median ESR (IQR) | 21 (11–36) | 22 (12–40) | 18 (9–32) | NA | NA | 19 (9–34) | 20 (10–33) | 9 (5–19) | 12 (6–16) |
| Median Patient Global VAS (IQR) | 54 (33–72) | 59 (40–75) | 56 (35–73) | 67 (47– 82) | 65 (45– 81) | 50 (29–71) | 47 (23–67) | 20 (10–51) | 18 (8–50) |
| Median HAQ (IQR) | 1.00 (0.5–1.38) | 1.13 (0.63–1.50) | 1.00 (0.50–1.38) | 1.12 (0.62– 1.75) | 1.00 (0.62– 1.62) | 0.62 (0.25–1.00) | 0.50 (0.13–0.88) | 0.50 (0.13–1.00) | NA |
| Three months | |||||||||
| Retention (%) | 1127 (94%) | 13 883 (95%) | 1676 (95%) | 7206 (96%) | 1774 (96%) | 1527 (90%) | 138 (100%) | 39 (57%) | 37 (100%) |
| Persistence (%) | 1122 (94%) | 13 825 (95%) | 1672 (95%) | 7149 (95%) | 1764 (95%) | 1492 (88%) | 138 (100%) | 38 (54%) | 36 (97%) |
| EULAR good response | 469 (47%) | 5045 (42%) | 662 (47%) | 2492 (41%) | 677 (43%) | 502 (35%) | 43 (32%) | 2 (10%) | 30 (81%) |
| Six months | |||||||||
| Retention (%) | 881 (84%) | 10 113 (84%) | 1184 (79%) | 5280 (83%) | 1359 (83%) | 1181 (72%) | 114 (100%) | 36 (38%) | 30 (100%) |
| Persistence (%) | 852 (81%) | 9752 (81%) | 1146 (77%) | 5118 (80%) | 1328 (81%) | 1152 (70%) | 114 (100%) | 36 (38%) | 30 (100%) |
| EULAR good response | 397 (44%) | 3872 (38%) | 482 (40%) | 1931 (44%) | 562 (47%) | 447 (41%) | 42 (37%) | 3 (17%) | 24 (80%) |
| 12 months | |||||||||
| Retention (%) | 943 (73%) | 11 268 (73%) | 1337 (66%) | 5311 (71%) | 1362 (72%) | 1050 (61%) | 103 (100%) | 48 (52%) | 23 (100%) |
| Persistence (%) | 888 (69%) | 10 494 (68%) | 1271 (62%) | 4950 (66%) | 1278 (68%) | 1002 (58%) | 103 (100%) | 44 (47%) | 20 (87%) |
| EULAR good response | 444 (42%) | 4548 (36%) | 564 (35%) | 2228 (50%) | 632 (52%) | 420 (43%) | 43 (43%) | 2 (9%) | 20 (87%) |
Characteristics of Swedish, Danish and Norwegian treatment cohorts at the start of TNF inhibitor (baseline), outcomes during 1 year and retention and persistence during 1 year of follow-up. Percentages are calculated based on available data, for proportions of missing data, see online supplemental table S7.
*Calculated on the subset of patients starting TNFi treatment in year 2006 or later.
†Seropositivity defined as diagnosed with ICD code M05.8 or M05.9 and seronegative defined as diagnosed with M06.0 or M06.8 (and, if available, negative for anti-CCP and IgM RF).
ACR, American Congress of Rheumatology; ARCTIC, Aiming for Remission in rheumatoid arthritis: a randomised trial examining the benefit of ultrasound in a Clinical TIght Control regimen; CRP, C reactive protein ; DANBIO, Danish Registry for Biologic Therapies in Rheumatology; DMARD, disease-modifying antirheumatic drug; DRB, Danish Rheumatologic Biobank; EIRA, Epidemiological Investigation of RA; ESR, erythrocyte sedimentation rate; EULAR, European Alliance of Associations for Rheumatology; ICD, International Classification of Diseases; NOR-DMARD, The Norwegian Antirheumatic Drug Register; NOR-VEAC, Norwegian Very Early Arthritic Clinic; RA, rheumatoid arthritis; SJC(28), swollen 28 joint count; SRQ, Swedish Rheumatology Quality; TJC(28), tender 28 joint count; ULRABIT, ULtrasound in Rheumatoid Arthritis patients starting BIologic Treatment; VAS, Visual Analogue Scale.