Table 1

Characteristics of patients with rheumatic immune-mediated inflammatory diseases compared with healthy controls

Patient characteristicsPatients (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. (%)
 High1148 (46)534 (58)
 Middle775 (31)246 (27)
 Low553 (22)139 (15)
Current smoking status—no. (%)387 (13)80 (7)
Coexisting conditions—no. (%)
Cardiovascular disease392 (13)83 (8)
Chronic pulmonary disease376 (12)65 (6)
Diabetes183 (6)37 (3)
Obesity497 (16)112 (10)
Immune-mediated inflammatory disease type—no. (%)
Rheumatoid arthritis1714 (56)N.A.
Psoriatic arthritis505 (16)N.A.
Ankylosing spondylitis459 (15)N.A.
Axial or peripheral spondyloarthritis76 (3)N.A.
Juvenile idiopathic arthritis51 (2)N.A.
Systemic lupus erythematosus175 (6)N.A.
Vasculitis81 (3)N.A.
Polymyalgia rheumatica125 (4)N.A.
Sjögren’s disease190 (6)N.A.
Systemic sclerosis61 (2)N.A.
Mixed connective tissue disease27 (0.9)N.A.
Other rheumatic diseases131 (4)N.A.
Disease activity—mean (SD)
RAPID-3 score11 (5.6)N.A.
BASDAI4 (2.0)N.A.
Immunosuppressive medication—no. (%)
No immunosuppressive medication679 (22)1098 (99.6)
csDMARDs1605 (52)3 (0.3)
 Methotrexate1183 (38)1 (0.1)
 Hydroxychloroquine362 (12)2 (0.2)
 Sulfasalazine176 (6)N.A.
bDMARDs1111 (36)N.A.
 TNF inhibitor885 (29)N.A.
 Tocilizumab34 (1)N.A.
 Abatacept55 (2)N.A.
 B-cell targeting therapy71 (2)N.A.
JAK inhibitor32 (1)N.A.
Oral glucocorticoids358 (12)1 (0.1)
Dose—median (IQR)5 (5–8)5
COVID-19 tests—no. (%)
PCR test1267 (41)451 (41)
 Solely negative results1068 (35)385 (35)
 At least one positive result199 (7)66 (6)
RBD-Ab bridging ELISA2343 (76)862 (78)
 Solely negative results2052 (67)742 (67)
 At least one positive result291 (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.