Table 1.
Baseline characteristics of the study population (total and stratified by immune-mediated inflammatory disease diagnosis)
| Parameter | Psoriatic arthritis | Axial spondyloarthritis | Psoriasis (without arthritis) | Total |
| N | 2293 | 1831 | 921 | 5045 |
| General | ||||
| Age (years) | 53.2 (12.8) | 46.9 (13.4) | 48.4 (13.6) | 50 (13.5) |
| ≤30 years | 110 (4.8) | 211 (11.5) | 100 (10.9) | 421 (8.3) |
| 31–50 years | 785 (34.2) | 900 (49.2) | 400 (43.4) | 2085 (41.3) |
| 51–65 years | 1032 (45) | 567 (31) | 336 (36.5) | 1935 (38.4) |
| 66–75 years | 280 (12.2) | 109 (6) | 59 (6.4) | 448 (8.9) |
| >75 years | 86 (3.8) | 44 (2.4) | 26 (2.8) | 156 (3.1) |
| Male sex | 1053 (45.9) | 996 (54.4) | 557 (60.5) | 2606 (51.7) |
| Ever-smoker | 566 (33.2) (N=1705) (Missing=588) |
313 (23.9) (N=1311) (Missing=520) |
334 (36.3) (N=921) (Missing=0) |
1213 (30.8) (N=3937) (Missing=1108) |
| Regions | ||||
| African Region | 5 (0.2) | 5 (0.3) | 4 (0.4) | 14 (0.3) |
| Eastern Mediterranean Region | 34 (1.5) | 31 (1.7) | 7 (0.8) | 72 (1.4) |
| European Region | 1707 (74.4) | 1396 (76.2) | 805 (87.4) | 3908 (77.5) |
| North American Region | 454 (19.8) | 221 (12.1) | 53 (5.8) | 728 (14.4) |
| South American Region | 62 (2.7) | 159 (8.7) | 46 (5) | 267 (5.3) |
| South-East Asian Region | 10 (0.4) | 8 (0.4) | 3 (0.3) | 21 (0.4) |
| Western Pacific Region | 21 (0.9) | 11 (0.6) | 3 (0.3) | 35 (0.7) |
| Time period | ||||
| Until 15 June 2020 | 744 (32.4) | 564 (30.8) | 417 (45.3) | 1725 (34.2) |
| From 16 June 2020 to 31 December 2020 | 1043 (45.5) | 880 (48.1) | 340 (36.9) | 2263 (44.9) |
| 1 January 2021 and later | 506 (22.1) | 387 (21.1) | 164 (17.8) | 1057 (21) |
| Ordinal outcome | ||||
| Not hospitalised, no death | 1850 (80.7) | 1576 (86.1) | 794 (86.2) | 4220 (83.6) |
| Hospitalised, no death | 392 (17.1) | 229 (12.5) | 115 (12.5) | 736 (14.6) |
| Death | 51 (2.2) | 26 (1.4) | 12 (1.3) | 89 (1.8) |
| Disease activity | (N=2014) (Missing=279) |
(N=1288) (Missing=532) |
(N=920) (Missing=1) |
N=4233 (Missing=812) |
| Remission/low disease activity | 1670 (82.9) | 1090 (83.9) | 740 (80.4) | 3500 (82.7) |
| Moderate/high disease activity | 344 (17.1) | 209 (16.1) | 180 (19.6) | 733 (17.3) |
| Comorbidities | (N=2266) (Missing=27) |
(N=1809) (Missing=22) |
(N=921) (Missing=0) |
N=4996 (Missing=49) |
| Hypertension | 744 (32.8) | 383 (21.2) | 196 (21.3) | 1323 (26.5) |
| Cardiovascular disease | 179 (7.9) | 88 (4.9) | 71 (7.7) | 338 (6.8) |
| COPD or asthma | 185 (8.2) | 114 (6.3) | 62 (6.7) | 361 (7. |
| Other chronic lung disease | 47 (2.1) | 30 (1.7) | 22 (2.4) | 99 (2) |
| Chronic kidney disease | 60 (2.6) | 24 (1.3) | 17 (1.8) | 101 (2) |
| Diabetes | 316 (13.9) | 126 (7) | 120 (13) | 562 (11.2) |
| Cancer | 65 (2.9) | 26 (1.4) | 24 (2.6) | 115 (2.3) |
| Obesity | 522 (23) | 262 (14.5) | 269 (29.2) | 1053 (21.1) |
| No of comorbidities | 1 (1.2) | 0.6 (1) | 1 (1.2) | 0.8 (1.1) |
| No comorbidity | 1077 (47.5) | 1124 (62.1) | 442 (48) | 2643 (52.9) |
| 1 comorbidity | 573 (25.3) | 418 (23.1) | 248 (26.9) | 1239 (24.8) |
| 2 comorbidities | 350 (15.4) | 181 (10) | 127 (13.8) | 658 (13.2) |
| ≥3 comorbidities | 266 (11.7) | 86 (4.8) | 104 (11.3) | 456 (9.1) |
| DMARDs (monotherapy or combination therapy) |
||||
| csDMARDs | 1068 (46.6) | 353 (19.3) | 107 (11.6) | 1528 (30.3) |
| Antimalarials | 30 (1.3) | 7 (0.4) | 0 | 37 (0.7) |
| Methotrexate | 889 (38.8) | 194 (10.6) | 100 (10.9) | 1183 (23.4) |
| Leflunomide | 94 (4.1) | 13 (0.7) | 0 | 107 (2.1) |
| Sulfasalazine | 119 (5.2) | 164 (9) | 0 | 283 (5.6) |
| Cyclosporine | 11 (0.5) | 0 | 8 (0.9) | 19 (0.4) |
| bDMARDs | 1341 (58.5) | 1347 (73.6) | 627 (68.1) | 3315 (65.7) |
| TNF inhibitors | 895 (39) | 1176 (64.2) | 227 (24.6) | 2298 (45.6) |
| IL-17 inhibitors | 301 (13.1) | 164 (9) | 145 (15.7) | 610 (12.1) |
| IL-23/IL-12+23 inhibitors | 145 (6.3) | 7 (0.4) | 255 (27.7) | 407 (8.1) |
| tsDMARDs | 111 (4.8) | 11 (0.6) | 19 (2.1) | 141 (2.8) |
| JAK inhibitors | 51 (2.2) | 11 (0.6) | 0 | 62 (1.2) |
| Apremilast | 60 (2.6) | 0 | 19 (2.1) | 79 (1.6) |
| No DMARD treatment | 234 (10.2) | 309 (16.9) | 179 (19.4) | 722 (14.3) |
| Other therapies | ||||
| Glucocorticoids (#) | 241 (10.7) (N=2242) (Missing=51) |
110 (6.3) (N=1760) (Missing=71) |
6 (0.7) (N=921) (Missing=0) |
357 (7.3) (N=4923) (Missing=122) |
| 0 mg/day <glucocorticoids ≤7.5 mg/day | 167 (7.5) (N=2215) (Missing=78) |
54 (3.1) (N=1724) (Missing=107) |
3 (0.3) (N=919) (Missing=2) |
224 (4.6) (N=4858) (Missing=187) |
| Glucocorticoids >7.5 mg/day | 46 (2.1) (N=2215) (Missing=78) |
19 (1.1) (N=1724) (Missing=107) |
1 (0.1) (N=919) (Missing=2) |
66 (1.4) (N=4858) (Missing=187) |
| NSAIDs | 512 (24.5) (N=2094) (Missing=199) |
553 (35.5) (N=1559) (Missing=272) |
32 (3.5) (N=921) (Missing=0) |
1097 (24) (N=4574) (Missing=471) |
| Acitretin | 3 (0.1) | 0 | 26 (2.8) | 29 (0.6) |
Data are N (column %) for categorical variables or mean (SD) for continuous variables. Table includes patients diagnosed with psoriasis without arthritis, psoriatic arthritis or axial spondyloarthritis, with a non-missing ordinal outcome and non-missing values for age, sex, time period and DMARDs. Further, patients receiving multiple b/tsDMARDs or DMARDs not typical for the three diagnoses were excluded, as well as patients labelled as having additional inflammatory rheumatic diseases (529 patients excluded in total). Data refer to patients with non-missing values for the respective variable; total N for patients with non-missing values is given in parentheses for variables with missing values; the total number of missing values is also given in parenthesis, for the applicable variables. (#) Includes patients with a missing glucocorticoid dosage.
bDMARD, biological disease-modifying anti-rheumatic drugs; BMI, body mass index; COPD, chronic obstructive pulmonary disease; csDMARD, conventional synthetic DMARD; DMARD, disease-modifying antirheumatic drug; IL, interleukin; JAK, Janus kinase; N, number; NSAID, non-steroidal anti-inflammatory drugs; TNF, tumour necrosis factor; tsDMARD, targeted synthetic DMARD.