Table 5. Multivariable logistic regression analysis of factors associated with flare, using either ‘I-RMD flare‘ or ‘new antirheumatic medication or dosage increase due to flare’ as the dependent variable.
| Covariates | Outcome: flare | Outcome: new medication or dosage increase due to flare | ||
| OR (95% CI) | P value | OR (95% CI) | P value | |
| Age, per decade of life | 0.90 (0.83 to 0.98) | 0.015 | 0.92 (0.81 to 1.04) | 0.18 |
| Female sex | 1.40 (1.05 to 1.87) | 0.021 | 1.24 (0.82 to 1.88) | 0.31 |
| Diagnostic group | ||||
| Inflammatory joint diseases | Reference | Reference | ||
| Connective tissue diseases | 0.68 (0.43 to 1.08) | 0.10 | 0.84 (0.45 to 1.57) | 0.59 |
| Vasculitis | 0.96 (0.57 to 1.62) | 0.88 | 0.93 (0.47 to 1.85) | 0.84 |
| Other I-RMD | 1.34 (0.56 to 3.21) | 0.51 | 1.09 (0.32 to 3.70) | 0.89 |
| Disease activity | ||||
| Remission | Reference | Reference | ||
| Low disease activity | 1.45 (1.08 to 1.94) | 0.013 | 1.47 (0.94 to 2.29) | 0.093 |
| Moderate/high disease activity | 1.37 (0.97 to 1.95) | 0.075 | 3.08 (1.91 to 4.97) | <0.001 |
| Vaccine | ||||
| Pfizer | Reference | Reference | ||
| Moderna | 0.87 (0.56 to 1.34) | 0.52 | 1.37 (0.77 to 2.45) | 0.29 |
| AstraZeneca | 1.13 (0.83 to 1.56) | 0.44 | 1.41 (0.90 to 2.22) | 0.13 |
| Other | 0.10 (0.01 to 0.74) | 0.023 | 0 | 1 |
| Antirheumatic medication | ||||
| None | Reference | Reference | ||
| Immunosuppressants | 0.32 (0.07 to 1.35) | 0.12 | 0 | 1 |
| Methotrexate | 0.57 (0.37 to 0.90) | 0.014 | 0.48 (0.26 to 0.89) | 0.019 |
| Leflunomide | 1.24 (0.60 to 2.57) | 0.57 | 0.76 (0.25 to 2.25) | 0.62 |
| Sulfasalazine | 0.85 (0.35 to 2.07) | 0.71 | 0.75 (0.22 to 2.62) | 0.65 |
| Antimalarials | 0.78 (0.43 to 1.40) | 0.41 | 0.47 (0.19 to 1.18) | 0.11 |
| TNFi | 0.55 (0.36 to 0.85) | 0.007 | 0.60 (0.33 to 1.09) | 0.096 |
| tsDMARDs | 0.56 (0.28 to 1.13) | 0.11 | 0.39 (0.13 to 1.18) | 0.094 |
| Rituximab | 0.27 (0.11 to 0.66) | 0.004 | 0.10 (0.01 to 0.77) | 0.027 |
| Other bDMARDs | 0.62 (0.38 to 1.01) | 0.055 | 0.57 (0.28 to 1.14) | 0.11 |
| Glucocorticoids | 0.69 (0.46 to 1.04) | 0.076 | 0.96 (0.56 to 1.65) | 0.89 |
| Cessation/reduction of antirheumatic medications at the time of vaccination | 4.76 (3.44 to 6.58) | <0.001 | 2.24 (1.33 to 3.78) | 0.002 |
For ‘Outcome: flare’, the total N was 7336 (272 flares); for ‘Outcome: new medication or dosage increase due to flare’, some outcome data were missing, and the total N was 5287 (121 flares). Missing values for vaccine type and disease activity were derived by multiple imputation using full conditional specification.
bDMARDsbiological disease-modifying antirheumatic drugsI-RMDinflammatory rheumatic and musculoskeletal diseaseTNFitumour necrosis factor inhibitorstsDMARDstargeted synthetic disease-modifying antirheumatic drugs