Baseline characteristics of subjects grouped by level of respiratory support: spontaneously-breathing patients (SB), patients on invasive mechanical ventilation (IMV) and patients on extracorporeal membrane oxygenation (ECMO)
| SB (n=178) | IMV (n=234) | ECMO (n=13) | P value | |
| Demographics | ||||
| Age, years | 65.0 (55.0, 71.9) | 64.3 (55.1, 73.4) | 56.7 (50.7, 57.8) | 0.01 |
| Body mass index | 30.8 (26.1, 36.9) | 32.7 (28.5, 38.4) | 35.9 (32.4, 41.8) | 0.01 |
| Sex, male | 84 (47.2%) | 160 (68.4%) | 10 (76.9%) | <0.01 |
| Race, White | 141 (79.2%) | 171 (73.1%) | 11 (84.6%) | 0.07 |
| Never smokers | 77 (47.2%) | 90 (46.2%) | 7 (53.8%) | 0.86* |
| Resident of nursing facility | 21 (12.4%) | 29 (14.9%) | 0 (0.0%) | 0.28* |
| Diabetes mellitus | 72 (40.4%) | 104 (44.4%) | 5 (38.5%) | 0.69 |
| Chronic obstructive lung disease | 35 (19.7%) | 37 (15.8%) | 2 (15.4%) | 0.58 |
| Congestive cardiac failure | 24 (13.5%) | 35 (15.0%) | 0 (0.0%) | 0.31 |
| Plasma biomarkers | ||||
| IL-6, pg/mL | 14.5 (5.9, 47.8) | 68.8 (14.0, 180.9) | 220.6 (88.1, 1112.0) | <0.01 |
| IL-8, pg/mL | 16.0 (8.6, 29.7) | 21.7 (14.2, 42.8) | 27.8 (15.0, 46.8) | <0.01 |
| Ang2, pg/mL | 2701.7 (1426.7, 4090.9) | 5634.2 (2860.3, 10 913.3) | 5927.3 (4170.2, 7592.2) | <0.01 |
| Procalcitonin, pg/mL | 107.5 (65.0, 283.9) | 633.7 (173.3, 1956.3) | 465.6 (196.6, 1261.5) | <0.01 |
| ST2, ng/mL | 87.8 (47.3, 168.0) | 211.1 (96.3, 378.9) | 190.1 (111.0, 253.9) | <0.01 |
| Pentraxin-3, pg/mL | 5791.2 (2621.5, 11 728.4) | 9599.2 (4680.4, 21 226.8) | 5525.4 (3748.7, 11 688.9) | 0.01 |
| sRAGE, pg/mL | 3979.1 (2447.0, 9137.2) | 6158.5 (3269.3, 12 653.0) | 1754.8 (1219.6, 5102.5) | <0.01 |
| sTNFR1, pg/mL | 3438.2 (2485.5, 5359.9) | 5601.7 (3375.9, 12 297.4) | 7283.8 (4650.7, 8515.4) | <0.01 |
| Hyperinflammatory phenotype | 5 (3.5%) | 12 (16.2%) | 2 (16.7%) | <0.01* |
| Radiographic parameters | ||||
| RALE Score, total | 20.0 (14.1, 26.7) | 26.0 (20.5, 34.0) | 44.5 (34.5, 48.0) | <0.01 |
| Lower quadrants RALE Score | 14.0 (10.0, 17.0) | 16.0 (12.5, 20.0) | 24.0 (22.0, 24.0) | <0.01 |
| Upper quadrants RALE Score | 6.0 (3.5, 9.9) | 10.0 (7.0, 14.0) | 22.5 (12.8, 24.0) | <0.01 |
| Time of CXR from symptom onset | 7.0 (3.0, 11.0) | 9.0 (6.0, 15.0) | 14.0 (11.0, 22.0) | <0.01 |
| Clinical outcomes | ||||
| In-hospital mortality | 33 (18.5%) | 163 (69.7%) | 6 (46.2%) | <0.01 |
| Discharge destination | ||||
| Home | 113 (63.5%) | 17 (7.3%) | 1 (7.7%) | <0.01 |
| Inpatient rehabilitation | 2 (1.1%) | 15 (6.4%) | 2 (15.4%) | <0.01 |
| Long-term acute care | 3 (1.7%) | 18 (7.7%) | 3 (23.1%) | <0.01 |
| Skilled nursing facility | 27 (15.2%) | 21 (9.0%) | 1 (7.7%) | 0.154 |
Continuous variables are reported in median (IQR). Categorical variables are reported as n (%).
*We only included patients with available clinical data or research biomarkers in analysis. Patients with unavailable data were excluded.
Ang2, Angiopoietin-2; CXR, chest X-ray; ECMO, extracorporeal membrane oxygenation; IL, interleukin; sRAGE, soluble receptor of advanced glycation end-products; ST2, suppression of tumorigenicity-2; sTNFR1, soluble Tumor Necrosis Factor Receptor 1.