Incidence rates, incidence rate ratios and HRs (95% CI) for serious infections in patients with RA and NIRMD by the infection, aetiology and site
| Infection | Number of cases (n) | Incidence rate (1000 patient years) | Incidence rate ratio (unadjusted)† | ||
| RA | NIRMD | RA | NIRMD | ||
| All infections | 1600 | 276 | 19.6 | 13.4 | 1.5 |
| (18.7–20.6) | (11.9–15.0) | (1.3–1.7) | |||
| Opportunistic | 85 | 7 | 1.0 | 0.3 | 3.0 |
| (0.8–1.2) | (0.2–0.7) | (1.4–7.7) | |||
| Herpes zoster | 53 | 6 | 0.6 | 0.3 | 2.2 |
| (0.5–0.8) | (0.1–0.6) | (0.9–6.2) | |||
| By aetiology | |||||
| Bacterial | 790 | 121 | 9.3 | 5.7 | 1.6 |
| (8.7–9.9) | (4.8–6.8) | (1.3–2.0) | |||
| Viral | 101 | 17 | 1.2 | 0.8 | 1.5 |
| (0.9–1.4) | (0.5–1.3) | (0.9–2.6) | |||
| Fungal | 41 | 2 | 0.5 | 0.1 | 5.1 |
| (0.3–0.6) | (0.0–0.4) | (1.3–43.3) | |||
| Unknown aetiology | 975 | 175 | 11.6 | 8.3 | 1.4 |
| (10.9–12.3) | (7.1–9.6) | (1.2–1.7) | |||
| By site | |||||
| Respiratory | 909 | 158 | 10.7 | 7.4 | 1.4 |
| (10.1–11.5) | (6.4–8.7) | (1.2–1.7) | |||
| Central nervous system | 17 | 3 | 0.2 | 0.1 | 1.4 |
| (0.1–0.3) | (0.0–0.4) | (0.4–7.5) | |||
| Abdominal | 80 | 10 | 0.9 | 0.5 | 2.0 |
| (0.7–1.1) | (0.2–0.9) | (1.0–4.3) | |||
| Urinary | 50 | 16 | 1.8 | 0.7 | 0.8 |
| (1.5–2.1) | (0.5–1.2) | (0.4–1.5) | |||
| Bloodstream including sepsis | 340 | 47 | 3.9 | 2.2 | 1.8 |
| (3.5–4.3) | (1.6–2.9) | (1.3–2.5) | |||
| Skin, bone and joint infections | 486 | 81 | 5.7 | 3.8 | 1.5 |
| (5.2–6.2) | (3.0–4.7) | (1.2–1.9) | |||
| Unknown site | 83 | 8 | 0.9 | 0.4 | 2.6 |
| (0.8–1.2) | (0.2–0.7) | (1.2–6.2) | |||
*See online supplementary appendix for details in the variables selected for each LASSO (Least Absolute Shrinkage and Selection Operator) model.
†Bold, p<0.05
NIRMD, non-inflammatory rheumatic and musculoskeletal disease; RA, rheumatoid arthritis.