Table 1.
Baseline demographic characteristics
| Variable | Overall (n = 610) | 1st wave (n = 397) | 2nd wave (n = 213) | p |
|---|---|---|---|---|
| Age, years | 66.8 ± 15.4 | 64.4 ± 15.2 | 71.2 ± 14.7 | 1.75 × 10 − 7 |
| Age by groups, n (%) | ||||
| 18–29 | 6 (1%) | 6 (1.5%) | 0 (0%) | |
| 30–39 | 16 (2.6%) | 14 (3.5%) | 2 (0.9%) | |
| 40–49 | 60 (9.8%) | 44 (11.1%) | 16 (7.5%) | |
| 50–64 | 199 (32.6%) | 143 (36%) | 56 (26.3%) | |
| 65–74 | 199 (32.6%) | 127 (32%) | 72 (33.8%) | |
| 75–84 | 85 (13.9%) | 42 (10.6%) | 43 (20.2%) | |
| ≥ 85 | 45 (7.4%) | 21 (5.3%) | 24 (11.3%) | |
| Males, n (%) | 410 (67.2%) | 264 (66.5%) | 146 (68.5%) | 0.608 |
| SaO2 to FIO2 ratio | 274.2 ± 110.1 | 275.2 ± 109.5 | 272.3 ± 111.3 | 0.761 |
| SaO2 to FIO2 ratio by groups, n (%) | ||||
| < 200 | 229 (37.5%) | 155 (39%) | 74 (34.7%) | |
| 200–299 | 128 (21%) | 78 (19.6%) | 50 (23.5%) | |
| 300–399 | 137 (22.5%) | 87 (21.9%) | 50 (23.5%) | |
| ≥ 400 | 116 (19%) | 77 (19.4%) | 39 (18.3%) | |
| Time to hospitalization, days | 6.5 ± 4.7 | 6.8 ± 5.1 | 5.8 ± 3.8 | 0.018 |
| Hypertension, n (%) | 262 (43%) | 169 (42.6%) | 93 (43.7%) | 0.795 |
| Diabetes, n (%) | 108 (17.7%) | 70 (17.6%) | 38 (17.8%) | 0.949 |
| Cardiac involvement, n (%) | 116 (19%) | 64 (16.1%) | 52 (24.4%) | 0.013 |
| Malignancy, n (%) | 77 (12.6%) | 43 (10.8%) | 34 (16%) | 0.069 |
| COPD, n (%) | 71 (11.6%) | 49 (12.3%) | 22 (10.3%) | 0.46 |
| Neurological involvement, n (%) | 50 (8.2%) | 25 (6.3%) | 25 (11.7%) | 0.02 |
| Renal involvement, n (%) | 34 (5.6%) | 20 (5%) | 14 (6.6%) | 0.431 |
| N comorbidities | 0.292 | |||
| 0 | 215 (35.2%) | 143 (36%) | 72 (33.8%) | |
| 1 | 194 (31.8%) | 131 (33%) | 63 (29.6%) | |
| 2 | 114 (18.7%) | 77 (19.4%) | 37 (17.4%) | |
| 3 + | 82 (13.4%) | 46 (11.6%) | 36 (16.9%) | |
| CRP, mg/dL | 9.3 ± 7.1 | 8.9 ± 7 | 10 ± 7.1 | 0.06 |
| Lymphocytes, cells/mm3 | 1013.3 ± 571.5 | 1035 ± 590.2 | 972.3 ± 533.2 | 0.2 |
| Ferritin, pg/mL | 831.5 (460.5–1391) | 916 (465–1528) | 731 (457.5–1140.5) | 5.12 × 10 − 5 |
| D-Dimer, ng/mL | 936 (560.5–1580.5) | 875 (534–1412) | 1009 (613–1918) | 0.027 |
| 4-week crude mortality | 128 (21%) | 74 (18.6%) | 54 (25.4%) | 0.052 |
All continuous values expressed as mean ± standard deviation or by median (interquartile range)
Significant p values (<0.05) are highlighted in bold