Incidence rates and incidence rate ratio (with 95% CI) by microorganism isolated for lookback and followup periods in patients with IgA vasculitis (IgAV) and controls.
| Lookback Period | IgAV, n = 314 | Controls, n = 982 | IRR | p | ||
|---|---|---|---|---|---|---|
| No. | IR | No. | IR | |||
| Group A streptococcus | 5 | 0.29 (0.09–0.69) | < 5 | 0.02 (0.002–0.10) | 16.1 (2.23–382.9) | 0.007 |
| Staphylococcal | < 5 | 0.24 (0.06–0.61) | 5 | 0.09 (0.003–0.21) | 2.6 (0.61–10.5) | 0.28 |
| H. influenzae | 0 | — | < 5 | 0.05 (0.01–0.16) | — | |
| Mycoplasma | 0 | — | 0 | — | — | |
| Parainfluenza | 0 | — | 5 | 0.09 (0.003–0.21) | — | |
| RSV | < 5 | 0.18 (0.03–0.52) | 0 | — | — | |
| Adenovirus | < 5 | 0.12 (0.013–0.43) | < 5 | 0.02 (0.002–0.21) | 6.4 (0.48–189.5) | 0.28 |
| Viral inducers | < 5 | 0.12 (0.013–0.0.43) | 0 | — | — | |
| Mycobacterium tub | < 5 | 0.06 (0.007–0.32) | 0 | — | — | |
| Salmonella | 0 | — | 0 | — | — | |
| Followup period | IgAV, n = 492 | Controls, n = 1236 | IRR | p | ||
| No. | IR | No. | IR | |||
| Group A streptococcus | < 5 | 0.009 (0.0001–0.052) | 0 | — | — | |
| Staphylococcal | 24 | 0.23 (0.01–0.34) | 28 | 0.08 (0.05–0.13) | 2.7 (1.55–4.67) | < 0.001 |
| H. influenzae | 5 | 0.047 (0.01–0.09) | < 5 | 0.003 (0.00004–0.0016) | 15.7 (2.18–374) | 0.007 |
| Mycoplasma | < 5 | 0.037 (0.01–0.097) | 2 | 0.006 (0.00006–0.021) | 6.3 (1.2–49.2) | 0.07 |
| Parainfluenza | 11 | 0.10 (0.05–0.18) | 10 | 0.03 (0.0014–0.055) | 3.47 (1.5–8.4) | 0.009 |
| RSV | 0 | — | 0 | — | — | |
| Adenovirus | 0 | — | 7 | 0.021 (0.008–0.043) | — | |
| Viral inducers | < 5 | 0.018 (0.002–0.069) | 0 | — | — | |
| Mycobacterium tub | 0 | — | 0 | — | — | |
| Salmonella | < 5 | 0.018 (0.002–0.069) | < 5 | 0.003 (0.0004–0.016) | 6.3 (0.47–185.9) | 0.29 |
Viral inducers include Epstein-Barr virus, zoster, cytomegalovirus, parvovirus. Small numbers (n < 5) have been confidentialized following HREC requirements. RSV: respiratory syncytial virus; IR: incidence rate; IRR: IR ratio; H. influenzae: Haemophilus influenzae.