Absolute and relative risks for COVID-19-related events and other outcomes in Swedish residents with rheumatoid arthritis (RA), and other inflammatory joint diseases (IJDs, defined as ankylosing spondylitis, psoriatic arthritis, other spondyloarthropathies and juvenile idiopathic arthritis) compared with matched general population comparator subjects 1 March through September 2020
| Condition | Outcome | N events (risk, %) in the IJD cohort | N events (risk, %) in the general population | Crude excess risk per 100 patients* | HR model 1† | HR model 2‡ |
| All | ||||||
| Hospitalisation, all causes | 8971 (8.1%) | 24 273 (5.0%) | 3.1 | 1.65 (1.61 to 1.69) | 1.18 (1.15 to 1.21) | |
| Hospitalisation, COVID-19 | 581 (0.5%) | 1443 (0.3%) | 0.2 | 1.77 (1.61 to 1.95) | 1.32 (1.19 to 1.46) | |
| Admission to ICU, COVID-19 | 45 (0.04%) | 162 (0.03%) | 0.01 | 1.22 (0.88 to 1.70) | 1.17 (0.82 to 1.66) | |
| Death, all causes | 1310 (1.2%) | 3036 (0.6%) | 0.6 | 1.90 (1.78 to 2.02) | 1.13 (1.05 to 1.21) | |
| Death, COVID-19 | 161 (0.10%) | 338 (0.07%) | 0.03 | 2.09 (1.73 to 2.52) | 1.18 (0.97 to 1.44) | |
| RA | ||||||
| Hospitalisation, all causes | 5275 (9.9%) | 13 072 (5.9%) | 4.0 | 1.71 (1.66 to 1.77) | 1.21 (1.17 to 1.25) | |
| Hospitalisation, COVID-19 | 379 (0.7%) | 784 (0.4%) | 0.3 | 2.02 (1.78 to 2.28) | 1.40 (1.23 to 1.60) | |
| Admission to ICU, COVID-19 | 31 (0.06%) | 79 (0.04%) | 0.02 | 1.63 (1.08 to 2.48) | 1.53 (0.98 to 2.40) | |
| Death, all causes | 968 (1.8%) | 2026 (0.9%) | 0.9 | 1.99 (1.85 to 2.15) | 1.18 (1.09 to 1.28) | |
| Death, COVID-19 | 134 (0.30%) | 245 (0.11%) | 0.19 | 2.28 (1.85 to 2.81) | 1.27 (1.02 to 1.59) | |
| Other IJD | ||||||
| Hospitalisation, all causes | 3696 (6.5%) | 11 201 (4.3%) | 2.2 | 1.54 (1.48 to 1.59) | 1.16 (1.11 to 1.20) | |
| Hospitalisation, COVID-19 | 202 (0.4%) | 659 (0.3%) | 0.1 | 1.41 (1.20 to 1.65) | 1.20 (1.02 to 1.41) | |
| Admission to ICU, COVID-19 | 14 (0.02%) | 83 (0.03%) | −0.01 | 0.78 (0.44 to 1.37) | 0.76 (0.43 to 1.37) | |
| Death, all causes | 342 (0.6%) | 1010 (0.4%) | 0.2 | 1.56 (1.38 to 1.76)‡ | 0.98 (0.86 to 1.12) | |
| Death, COVID-19 | 27 (0.05%) | 93 (0.04%) | 0.01 | 1.34 (0.87 to 2.05) | 0.83 (0.54 to 1.28) |
*Defined as the difference between the risk in the inflammatory joint disease cohort and that in its matched population comparator cohort.
†Cox model unadjusted, matched for age, sex and geographical region; general population comparators are the reference.
‡Cox model additionally adjusted for history of cancer, diabetes, heart failure, ischaemic heart disease, infections, lung disease, kidney failure, stroke, joint surgery, venous thromboembolism, country of birth, highest educational achievement, civil status, region, number of days in hospital (in previous 1 year and 10 years).
ICU, intensive care unit.