Unadjusted and adjusted logistic regression models examining the factors associated with seropositivity
| Seropositivity rate, n (%) | Unadjusted OR (95% CI) | Adjusted OR (95% CI) | P value | |
| Age >65 years, n=246 | 195 (79.27) | 0.33 (0.22 to 0.52) | 0.43 (0.25 to 0.75) | 0.002 |
| AIIRD diagnosis | ||||
| PsA, n=165 | 160 (96.97) | Reference | Reference | |
| RA, n=263 | 216 (82.13) | 0.14 (0.06 to 0.37) | 0.31 (0.11 to 0.82) | 0.02 |
| AxSpA, n=68 | 67 (98.53) | 2.09 (0.24 to 18.26) | 2.01 (0.23 to 17.72) | 0.52 |
| SLE, n=101 | 93 (92.08) | 0.36 (0.12 to 1.14) | 0.35 (0.11 to 1.16) | 0.08 |
| IIM, n=19 | 7 (36.84) | 0.02 (0.01 to 0.07) | 0.06 (0.02 to 0.27) | <0.001 |
| LVV, n=21 | 20 (95.24) | 0.63 (0.07 to 5.63) | 0.82 (0.09 to 7.54) | 0.86 |
| AAV, n=26 | 8 (30.77) | 0.01 (0.004 to 0.05) | 0.04 (0.01 to 0.17) | <0.001 |
| Other vasculitis, n=23 | 19 (82.61) | 0.15 (0.04 to 0.6) | 0.26 (0.06 to 1.22) | 0.09 |
| AIIRD treatments | ||||
| Anti-CD20, n=87 | 36 (41.38) | 0.05 (0.03 to 0.08) | 0.13 (0.07 to 0.24) | <0.001 |
| Anti-CD20 monotherapy, n=28 | 11 (39.29) | 0.07 (0.03 to 0.16) | 0.92 (0.33 to 2.57) | 0.87 |
| Anti-CD20 +MTX, n=14 | 5 (35.71) | 0.07 (0.02 to 0.21) | 0.94 (0.23 to 3.89) | 0.93 |
| MTX, n=176 | 148 (84.09) | 0.64 (0.4 to 1.03) | 0.58 (0.31 to 1.07) | 0.08 |
| MTX monotherapy, n=41 | 38 (92.68) | 1.75 (0.53 to 5.79) | 1.84 (0.5 to 6.74) | 0.36 |
| GC, n=130 | 86 (66.15%) | 0.16 (0.1 to 0.29) | 0.48 (0.26 to 0.87) | 0.02 |
| TNFi, n=172 | 167 (97.09) | 5.6 (2.24 to 14.0) | 1.89 (0.68 to 5.24) | 0.22 |
| TNFi monotherapy, n=121 | 119 (98.35) | 9.46 (2.3 to 38.87) | 2.58 (0.56 to 11.94) | 0.22 |
| TNFi +MTX, n=29 | 27 (93.1) | 1.86 (0.44 to 7.94) | 1.46 (0.31 to 6.91) | 0.63 |
| IL6i, n=37 | 37 (100) | NA | NA | NA |
| IL6i monotherapy, n=19 | 19 (100) | NA | NA | NA |
| IL6i+MTX, n=7 | 7 (100) | NA | NA | NA |
| IL17i, n=48 | 47 (97.92) | 6.73 (0.92 to 49.32) | 1.42 (0.16 to 12.83) | 0.75 |
| IL17 monotherapy, n=37 | 37 (100) | NA | NA | NA |
| IL17 +MTX, n=7 | 6 (85.71) | 0.81 (0.1 to 6.8) | 0.25 (0.02 to 2.7) | 0.25 |
| Abatacept, n=16 | 10 (62.5) | 0.21 (0.08 to 0.6) | 0.14 (0.04 to 0.43) | <0.001 |
| Abatacept monotherapy, n=7 | 5 (71.43) | 0.33 (0.06 to 1.74) | 0.2 (0.033 to 1.16) | 0.073 |
| Abatacept+MTX, n=5 | 2 (40) | 0.09 (0.01 to 0.53) | 0.07 (0.01 to 0.48) | 0.007 |
| JAKi monotherapy, n=21 | 19 (90.48) | 1.29 (0.3 to 5.63) | 0.72 (0.15 to 3.48) | 0.68 |
| JAKi+MTX, n=24 | 22 (91.67) | 1.5 (0.35 to 6.48) | 1.78 (0.38 to 8.35) | 0.46 |
| MMF, n=28 | 18 (64.29) | 0.22 (0.1 to 0.5) | 0.1 (0.03 to 0.34) | 0.0013 |
| MMF monotherapy, n=5 | 3 (60) | 0.2 (0.03 to 1.21) | 0.11 (0.02 to 0.83) | 0.03 |
AAV, antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis; AIIRD, autoimmune inflammatory rheumatic diseases; anti-CD20, CD20 inhibitors; AxSpA, axial spondyloarthritis; GC, glucocorticoids; IIM, idiopathic inflammatory myositis; IL6i, interleukin 6 inhibitors; IL17i, interleukin 17 inhibitors; JAKi, Janus kinase inhibitors; LVV, large vessel vasculitis; MMF, mycophenolate mofetil; MTX, methotrexate; PsA, psoriatic arthritis; RA, rheumatoid arthritis; SLE, systemic lupus erythematosus; TNFi, tumour necrosis factor inhibitors.