Table 1.
Characteristics of patients with rheumatic immune-mediated inflammatory diseases compared with healthy controls
| Patient characteristics | Patients (n=3080) | Healthy controls (n=1102) |
| Age, years—mean (SD) | 57 (14) | 55 (14) |
| Female sex—no. (%) | 1990 (65) | 759 (69) |
| Male sex—no. (%) | 1089 (35) | 343 (31) |
| Body mass index, kg/m2—mean (SD) | 26 (5) | 25 (4) |
| Caucasian race—no. (%) | 2346 (86) | 909 (92) |
| Educational level—no. (%) | ||
| High | 1148 (46) | 534 (58) |
| Middle | 775 (31) | 246 (27) |
| Low | 553 (22) | 139 (15) |
| Current smoking status—no. (%) | 387 (13) | 80 (7) |
| Coexisting conditions—no. (%) | ||
| Cardiovascular disease | 392 (13) | 83 (8) |
| Chronic pulmonary disease | 376 (12) | 65 (6) |
| Diabetes | 183 (6) | 37 (3) |
| Obesity | 497 (16) | 112 (10) |
| Immune-mediated inflammatory disease type—no. (%) | ||
| Rheumatoid arthritis | 1714 (56) | N.A. |
| Psoriatic arthritis | 505 (16) | N.A. |
| Ankylosing spondylitis | 459 (15) | N.A. |
| Axial or peripheral spondyloarthritis | 76 (3) | N.A. |
| Juvenile idiopathic arthritis | 51 (2) | N.A. |
| Systemic lupus erythematosus | 175 (6) | N.A. |
| Vasculitis | 81 (3) | N.A. |
| Polymyalgia rheumatica | 125 (4) | N.A. |
| Sjögren’s disease | 190 (6) | N.A. |
| Systemic sclerosis | 61 (2) | N.A. |
| Mixed connective tissue disease | 27 (0.9) | N.A. |
| Other rheumatic diseases | 131 (4) | N.A. |
| Disease activity—mean (SD) | ||
| RAPID-3 score | 11 (5.6) | N.A. |
| BASDAI | 4 (2.0) | N.A. |
| Immunosuppressive medication—no. (%) | ||
| No immunosuppressive medication | 679 (22) | 1098 (99.6) |
| csDMARDs | 1605 (52) | 3 (0.3) |
| Methotrexate | 1183 (38) | 1 (0.1) |
| Hydroxychloroquine | 362 (12) | 2 (0.2) |
| Sulfasalazine | 176 (6) | N.A. |
| bDMARDs | 1111 (36) | N.A. |
| TNF inhibitor | 885 (29) | N.A. |
| Tocilizumab | 34 (1) | N.A. |
| Abatacept | 55 (2) | N.A. |
| B-cell targeting therapy | 71 (2) | N.A. |
| JAK inhibitor | 32 (1) | N.A. |
| Oral glucocorticoids | 358 (12) | 1 (0.1) |
| Dose—median (IQR) | 5 (5–8) | 5 N.A. |
| COVID-19 tests—no. (%) | ||
| PCR test | 1267 (41) | 451 (41) |
| Solely negative results | 1068 (35) | 385 (35) |
| At least one positive result | 199 (7) | 66 (6) |
| RBD-Ab bridging ELISA | 2343 (76) | 862 (78) |
| Solely negative results | 2052 (67) | 742 (67) |
| At least one positive result | 291 (9) | 120 (11) |
Data are mean (SD), median (IQR) or n (%). Educational levels were based on the International Standard Classification of Education. Other rheumatic diseases included Raynaud’s disease, sarcoidosis, myositis, dermatomyositis, polymyositis, reactive arthritis, relapsing polychondritis, remitting seronegative symmetrical synovitis with pitting oedema, IgG4-mediated diseases, SAPHO syndrome, oeosinophilic fasciitis and diffuse idiopathic skeletal hyperostosis. Other bDMARDs were ustekinumab, secukinumab, anakinra, ixekizumab and sarilumab. Other csDMARDs were leflunomide, azathioprine, ciclosporin and gold injections. One person can be diagnosed with more than one autoimmune disease and receive more than one immunosuppressive drug. RAPID-3 scores were only assessed in patients with RA. BASDAI scores were only assessed in patients with AS, PsA or axial/peripheral SpA. Healthy controls treated with csDMARDs were diagnosed with lichen planopilaris, chronic discoid lupus erythematosus. Only data on educational level and race had missing values, valid percentages are shown.
AS, ankylosing spondylitis; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; bDMARDs, biological DMARDs; csDMARDs, conventional synthetic disease-modifying antirheumatic drugs; JAK, janus kinase; N.A., not applicable; PsA, psoriatic arthritis; RA, rheumatoid arthritis; RAPID-3, Routine Assessment of Patient Index Data-3; RBD-Ab, receptor binding domain antibody; SAPHO, synovitis, acne, pustulosis, hyperostosis, osteitis; SpA, spondyloarthritis; TNF, tumour necrosis factor.