Table 1.
Cohort Characteristics at Day 0
| Variable | All Patients | Supplemental O2 | Invasive Ventilation |
|---|---|---|---|
| No. | 225 | 151 | 74 |
| Age, yr | 61 (18) | 60 (19) | 64 (16) |
| Female, n (%) | 103 (46) | 74 (49) | 29 (39) |
| Body mass index | 31.0 (7.6) | 31.3 (7.5) | 30.4 (8.0) |
| Comorbidities, n (%) | |||
| Heart failure | 27 (12) | 20 (13) | 7 (9) |
| Coronary disease | 21 (9) | 17 (11) | 4 (5) |
| Hypertension | 112 (50) | 74 (49) | 38 (51) |
| COPD without home O2 | 16 (7) | 14 (9) | 2 (3) |
| COPD with home O2 | 6 (3) | 4 (3) | 2 (3) |
| Current smoker | 63 (28) | 43 (19) | 20 (27) |
| Prehospital baseline creatinine, mg/dl | 1.2 (1.1) | 1.1 (0.5) | 1.6 (1.8) |
| Chronic kidney disease without hemodialysis | 31 (14) | 19 (13) | 12 (16) |
| End-stage renal disease | 3 (1) | 0 (0) | 3 (4) |
| Non–insulin-dependent diabetes | 56 (25) | 29 (19) | 27 (36) |
| Insulin-dependent diabetes | 16 (7) | 12 (8) | 4 (5) |
| Immunosuppression | 20 (9) | 10 (7) | 10 (14) |
| Active malignancy | 12 (5) | 7 (5) | 5 (7) |
| Home ACE inhibitor | 20 (9) | 11 (7) | 9 (12) |
| Presenting characteristics | |||
| Symptom duration, days | 7 (4–11) | 7 (4–11) | 7 (3–10) |
| Bilateral radiographic opacities, n (%) | 188 (84) | 122 (81) | 66 (89) |
| S/F | 210 (105) | 264 (87) | 101 (24) |
| P/F | — | (n = 0) | 194 (52) (n = 59) |
| Hypoxemia severity* | |||
| P:F > 300 or S:F > 315 | 54 (24) | 54 (36) | 0 (0) |
| P:F 200–300 or S:F 235–315 | 46 (20) | 46 (30) | 0 (0) |
| P:F < 200 or S:F < 235 | 125 (56) | 51 (34) | 74 (100) |
| ARDS on Day 0† | 145 (64) | 79 (52) | 66 (89) |
| Initial SOFA score | 4.4 (3.8) | 2.4 (2.6) | 8.5 (2.5) |
| Mean arterial pressure, mm Hg | 72 (13) | 77 (11) | 63 (11) |
| Lactate, mmol/L | 2.0 (1.3) | 1.7 (0.8) | 2.3 (1.6) |
| High-sensitivity troponin-T, ng/L | 11 (6–31) | 8 (6–24) | 17 (7–47) |
| Creatinine, mg/dl | 1.3 (1.3) | 1.1 (0.9) | 1.6 (1.8) |
| Fold-change in creatinine from prehospital baseline | 1.11 (0.7) | 1.06 (1.06) | 1.21 (0.87) |
| Bicarbonate | 23.1 (3.7) | 23.5 (3.7) | 22.2 (3.5) |
| C-reactive protein, mg/dl | 137.8 (69.1–189.3) | 104.2 (58.4–168.3 | 149.5 (124.7–225.0) |
| D-dimer, ng/ml | 1,201 (760–1,985) | 1,082 (710–1,784) | 1,533 (951–2,301) |
| Absolute lymphocyte count | 0.94 (0.62–1.27) | 1.01 (0.71–1.36) | 0.78 (0.49–1.06) |
| Absolute neutrophil count | 5.70 (4.22–7.96) | 5.27 (3.92–7.54) | 6.57 (4.93–8.23) |
| Platelet count | 209 (160–281) | 208 (160–280) | 209 (158–287) |
| In-hospital treatments | |||
| Steroids | 23 (10) | 14 (9) | 9 (12) |
| Remdesivir | 6 (3) | 4 (3) | 2 (3) |
| Tocilizumab | 16 (7) | 15 (10) | 1 (1) |
| Inhaled nitric oxide | 12 (5) | 4 (3) | 8 (11) |
Definition of abbreviations: ACE = angiotensin-converting enzyme; ARDS = acute respiratory distress syndrome; COPD = chronic obstructive pulmonary disease; S:F = SpO2/FiO2 ratio; SOFA = Sequential Organ Failure Assessment; SpO2 = oxygen saturation as measured by pulse oximetry; P:F = PaO2/FiO2 ratio.
Continuous variables presented as mean (SD) or as median (interquartile range).
Hypoxemia severity based hierarchically on P:F or, when P:F unavailable, the S:F.
Indicates ARDS by modified Berlin criteria (i.e., both bilateral radiographic opacities and either P:F < 300 or S:F < 315 believed unlikely to be in the setting of cardiac failure or volume overload). Hypoxemia despite > 5 cm H2O of positive end-expiratory pressure could not be assessed among patients who received only supplemental oxygen.