Baseline characteristics
| Characteristic | Patients with biomarkers at day 1 (n=210) | Patients with biomarkers at day 1 and follow-up visit (n=97) | Control (n=50) |
| Age in years, median (IQR) | 64 (51–76) | 55 (47–67) | 43 (40–49) |
| Female sex, no (%) | 99 (47.1) | 43 (44.3) | 33 (66) |
| Current or former smokers, no (%) | 52 (24.8) | 27 (27.8) | 5 (10) |
| Coexisting conditions, no (%) | |||
| Any | 142 (67.6) | 52 (55.6) | 7 (14) |
| Hypertension | 92 (43.8) | 27 (27.8) | 3 (6) |
| Diabetes | 48 (22.9) | 15 (15.5) | 0 (0) |
| Dyslipidaemia | 64 (30.5) | 27 (27.8) | 4 (8) |
| Chronic heart disease | 26 (12.4) | 8 (8.2) | 1 (2) |
| Chronic renal disease | 26 (12.4) | 1 (1) | 1 (2) |
| Chronic liver disease | 6 (2.9) | 4 (4.1) | 1 (2) |
| Neurological disease | 25 (11.9) | 3 (3.1) | 0 (0) |
| Chronic respiratory disease | 23 (11) | 12 (12.4) | 1 (2) |
| Days since onset of symptoms, median (IQR) | 7 (5–10) | 7 (6–10) | NA |
| SpO2/FiO2 at admission (IQR) | 452.4 (429–461.9) | 452.4 (438.1–457.1) | NA |
| Radiological data at admission | |||
| Bilateral infiltrates, no (%) | 117 (55.7) | 61 (62.9) | NA |
| Severity | |||
| PSI score, median (IQR) | 68 (48–92) | 55 (44–72) | NA |
| SOFA score, median (IQR) | 1 (0–2) | 1 (0–1) | NA |
| Respiratory support | |||
| HFNC/CPAP/NIV, no (%) | 22 (10.6) | 14 (14.4) | NA |
| MV, no (%) | 16 (7.6) | 9 (9.3) | NA |
| Median length of MV, days, median (IQR) | 14 (11–17) | 12 (10–16) | NA |
| Treatment | |||
| Remdesivir, no (%) | 1 (0.5) | 0 (0) | NA |
| Steroids, no (%) | 74 (35.2) | 28 (28.9) | NA |
| Hydroxychloroquine/chloroquine, no (%) | 178 (84.8) | 95 (97.9) | NA |
| Lopinavir/ritonavir, no (%) | 39 (18.6) | 28 (28.9) | NA |
| Tocilizumab, no (%) | 35 (16.7) | 18 (18.6) | NA |
| Statins (chronic treatment), no (%) | 51 (24.3) | 21 (21.6) | 4 (8) |
| Aspirin (chronic treatment), no (%) | 20 (9.5) | 4 (4.1) | 0 (0) |
| Outcomes | |||
| Length of hospitalisation, days, median (IQR) | 12 (9–20) | 12 (10–16) | NA |
| In-hospital mortality, no (%) | 27 (12.9) | NA | NA |
HFNC, high-flow nasal cannula; MV, mechanical ventilation; NA, not applicable; NIV, non-invasive ventilation; PSI, Pneumonia Severity Index; SOFA, Sequential Organ Failure Assessment; SpO2/FiO2, peripheral blood oxygen saturation/fraction of inspired oxygen.