Table 1. Patient characteristics comparing the spring and autumn period, ECMO = extracorporeal membrane oxygenation.
The Elixhauser Comorbidity Index is a method of categorizing comorbidities of patients based on the (ICD) diagnosis codes in administrative data.
| Patients by month of hospital admission | |||
|---|---|---|---|
| Variable | Total | Admission between February 2020 and May 2020 | Admission between October 2020 and February 2021 |
| Number of patients | 17023 | 2376 | 13998 |
| Age (years) | |||
| Mean (SD) | 69.3 (13.1) | 68.1 (13.3) | 69.7 (12.9) |
| Median (IQR) | 71.0 (61.0, 80.0) | 70.0 (60.0, 79.0) | 71.0 (62.0, 80.0) |
| 18–49 years | 1,304 (7.7%) | 204 (8.6%) | 1,010 (7.2%) |
| 50–59 years | 2,328 (13.7%) | 380 (16.0%) | 1,840 (13.1%) |
| 60–69 years | 4,152 (24.4%) | 556 (23.4%) | 3,418 (24.4%) |
| 70–79 year | 4,847 (28.5%) | 726 (30.6%) | 3,956 (28.3%) |
| ≥ 80 years | 4,392 (25.8%) | 510 (21.5%) | 3,774 (27.0%) |
| Male | 10,926 (64.2%) | 1,565 (65.9%) | 8,913 (63.7%) |
| Female | 6,097 (35.8%) | 811 (34.1%) | 5,085 (36.3%) |
| Elixhauser comorbidities | |||
| Hypertension | 11,708 (68.8%) | 1,545 (65.0%) | 9,717 (69.4%) |
| Diabetes | 7,313 (43.0%) | 947 (39.9%) | 6,097 (43.6%) |
| Cardiac arrhythmias | 7,311 (42.9%) | 1,079 (45.4%) | 5,966 (42.6%) |
| Renal failure | 4,979 (29.2%) | 627 (26.4%) | 4,203 (30.0%) |
| Congestive heart failure | 5,871 (34.5%) | 786 (33.1%) | 4,853 (34.7%) |
| Chronic pulmonary disease | 3,378 (19.8%) | 469 (19.7%) | 2,780 (19.9%) |
| Obesity | 2,659 (15.6%) | 354 (14.9%) | 2,201 (15.7%) |
| Charlson comorbidity index: 0 | 3,118 (18.3%) | 455 (19.1%) | 2,537 (18.1%) |
| Charlson comorbidity index: 1 | 3,495 (20.5%) | 507 (21.3%) | 2,858 (20.4%) |
| Charlson comorbidity index: 2 | 2,814 (16.5%) | 425 (17.9%) | 2,285 (16.3%) |
| Charlson comorbidity index: 3–4 | 4,256 (25.0%) | 558 (23.5%) | 3,564 (25.5%) |
| Charlson comorbidity index: ≥ 5 | 3,340 (19.6%) | 431 (18.1%) | 2,754 (19.7%) |
| Patients transferred between hospitals | 5,543 (32.6%) | 856 (36.0%) | 4,373 (31.2%) |
| Length of hospital stay (days) | |||
| Mean (SD) | 32.9 (33.8) | 37.2 (38.7) | 31.1 (31.0) |
| Median (IQR) | 22.0 (13.0, 41.0) | 26.0 (13.0, 49.0) | 21.0 (12.0, 38.0) |
| Ventilation (days) | |||
| Mean (SD) | 13.9 (17.7) | 17.4 (19.2) | 13.1 (17.2) |
| Median (IQR) | 8.0 (2.3, 18.2) | 11.9 (4.8, 23.4) | 7.3 (2.1, 17.2) |
| Tracheostomy | 4,017 (23.6%) | 747 (31.4%) | 3,061 (21.9%) |
| ECMO | 1,129 (6.6%) | 190 (8.0%) | 864 (6.2%) |
| Dialysis | 3,781 (22.2%) | 723 (30.4%) | 2,891 (20.7%) |
| Type of ventilation | |||
| Invasive ventilation only (IMV) | 7,235 (42.5%) | 1,772 (74.6%) | 5,105 (36.5%) |
| Non-invasive ventilation only (NIV) | 4,469 (26.3%) | 221 (9.3%) | 4,125 (29.5%) |
| Non-invasive ventilation failure (NIV-F) | 3,472 (20.4%) | 214 (9.0%) | 3,156 (22.5%) |
| Duration of ventilation between 1–6 hours | 1,152 (6.8%) | 85 (3.6%) | 1,026 (7.3%) |
| No ventilation procedure code | 695 (4.1%) | 84 (3.5%) | 586 (4.2%) |
| In-hospital mortality | 9,066 (53.3%) | 1,204 (50.7%) | 7,607 (54.3%) |