Baseline characteristics, severity and outcomes of 2119 adults admitted to hospital with confirmed NIRV and influenza virus infections
| Variable | No. (%) of patients with influenza* n = 963 | No. (%) of patients with NIRV* n = 1156 | No. (%) of patients with RSV* n = 274 | No. (%) of patients with hRV* n = 315 | No. (%) of patients with hCoV* n = 174 | p value† |
|---|---|---|---|---|---|---|
| Age, yr | ||||||
| Mean ± SD | 68.8 ± 18.4 | 66.4 ± 20.4 | 69.4 ± 18.5 | 61.9 ± 21.4 | 66.4 ± 20.3 | 0.005 |
| Median (IQR) | 72.0 (58.0–84.0) | 69.0 (54.0–83.0) | 72.0 (61.0–82.5) | 66.0 (45.0–80.0) | 68.5 (55.8–83.3) | 0.030 |
| Sex, male | 472 (49.1) | 559 (48.4) | 127 (46.4) | 162 (51.4) | 83 (47.7) | 0.728 |
| Immunocompromised‡ | 208 (25.1) | 276 (30.3) | 64 (28.8) | 84 (34.4) | 40 (27.4) | 0.016 |
| Pregnant female‡ | 21 (4.4) | 33 (5.8) | 4 (2.8) | 12 (8.5) | 8 (4.7) | 0.322 |
| Illness onset to diagnosis, median (IQR), d§ | 3.0 (2.0–6.0) | 4.0 (2.0–7.0) | 4.0 (2.0–7.0) | 3.0 (2.0–7.0) | 3.0 (2.0–7.0) | 0.016 |
| LRT samples for diagnosis§ | 45 (4.7) | 69 (6.0) | 3 (1.1) | 19 (6.1) | 8 (4.6) | 0.187 |
| Hospital-acquired infection§ | 131 (13.6) | 169 (14.6) | 34 (12.4) | 41 (13.0) | 34 (19.5) | 0.504 |
| Respiratory support¶ | 181 (18.8) | 243 (21.1) | 56 (20.7) | 60 (19.2) | 34 (19.5) | 0.182 |
| ICU admission | 159 (16.5) | 210 (18.2) | 50 (18.2) | 50 (15.9) | 30 (17.2) | 0.317 |
| ICU length-of-stay, median (IQR), d | 6.0 (3.0–13.3) | 6.0 (3.0–13.0) | 6.0 (3.0–9.0) | 7.0 (2.5–14.5) | 5.0 (2.8–8.3) | 0.902 |
| Bacterial isolates** | ||||||
| Blood samples | 19 (3.7) | 52 (4.5) | 11 (4.0) | 17 (5.4) | 9 (5.2) | 0.443 |
| Respiratory samples | 22 (4.3) | 256 (22.2) | 46 (16.8) | 74 (23.5) | 30 (17.2) | < 0.001 |
| Hospital length-of-stay, median (IQR), d†† | 4.0 (2.0–9.0) | 5.0 (2.0–10.0) | 5.0 (3.0–9.0) | 4.0 (2.0–8.0) | 4.0 (2.0–10.0) | 0.041 |
| 30-day mortality from admission†† | 45 (5.4) | 77 (7.8) | 20 (8.3) | 19 (6.9) | 11 (7.9) | 0.043 |
| 30-day mortality from diagnosis†† | 62 (6.5) | 98 (8.4) | 26 (9.5) | 21 (6.6) | 16 (9.2) | 0.077 |
Note: hCoV = human coronavirus, hRV = human rhinovirus, ICU = intensive care unit, IQR = interquartile range, LRT = lower respiratory tract, NIRV = noninfluenza respiratory virus, RSV = respiratory syncytial virus, SD = standard deviation.
↵* Unless indicated otherwise.
↵† Comparison between all NIRV and influenza patients (χ2 test, Mann–Whitney U test and Student t test were used, whenever appropriate).
↵‡ Immunocompromised patients (n = 1738) included recipients of transplant, patients on immunosuppressants (including long-term corticosteroids), patients undergoing chemotherapy and patients with neutropenia, active malignancy or acquired immunodeficiency. Pregnant female reflects the frequency among female subjects only.
↵§ Illness onset to diagnosis is defined as the time between illness onset and diagnostic specimen collection; the onset date was undetermined in about 23.8% of cases. The median time interval between admission and diagnostic specimen collection for patients with hospital-acquired infections was 12 (IQR 4–24) days. Lower respiratory tract (LRT) includes patients for whom samples were required to establish the diagnosis, which included bronchoalveolar lavage, bronchial wash or aspirate and endotracheal aspirates.
↵¶ Respiratory support includes patients who required intubation and mechanical ventilation, noninvasive ventilation (e.g., bilevel positive airway pressure), high-flow oxygen therapy (HFOT) and extracorporeal membrane oxygenation (ECMO). Data on supplemental oxygen use was available from 1 centre (n = 628; influenza 68.0%, NIRV 63.6%, p > 0.05).
↵** Bacterial isolates includes cases with ≥ 1 bacterial pathogens identified in cultures of blood or respiratory samples (Appendix 2).
↵†† Hospital length-of-stay was calculated for survivors with community-acquired infections (n = 1681). Thirty-day mortality from admission includes only patients with community-acquired infections (n = 1817). Thirty-day mortality from diagnosis includes all 2119 patients. Thirty-day mortality of patients admitted to the ICU was 16.4% and 21.0% among influenza (n = 159) and NIRV (n = 210) patients, respectively (92% of ICU admissions occurred on day 1–2 of hospitalization); mortality of non-ICU cases was 4.5% and 5.7%, respectively.