TABLE 1.
Patient characteristics
| Characteristics | PP group | Control group | Total |
| Subjects, n | 29 | 32 | 61 |
| Age, years | 61.0±16.7 | 57.5±14.8 | 59.2±15.7 |
| Male gender | 18 (62.1) | 20 (62.5) | 38 (62.3) |
| BMI, kg·m−2 | 26.9±4.1 | 26.1±3.9 | 26.5±4 |
| Comorbidities | |||
| Cerebrovascular disease | 2 (6.9) | 1 (3.1) | 3 (4.9) |
| Hypertension | 12 (41.4) | 6 (18.7) | 18 (29.5) |
| Cardiovascular disease | 1 (3.4) | 2 (6.2) | 3 (4.9) |
| Diabetes | 3 (10.3) | 2 (6.2) | 5 (8.2) |
| Chronic renal failure | 2 (6.9) | 1 (3.1) | 3 (4.9) |
| Obesity (BMI ≥34 kg·m−2) | 2 (6.9) | 2 (6.2) | 4 (6.6) |
| COPD | 1 (3.4) | 1 (3.1) | 2 (3.3) |
| Other chronic pulmonary disease | 3 (10.3) | 2 (6.2) | 5 (8.2) |
| History of solid malignancy | 5 (16.4) | 5 (15.6) | 10 (16.4) |
| History of haematological malignancy | 2 (6.9) | 5 (15.6) | 7 (11.5) |
| Vaccinated for SARS-CoV-2 | 16 (55.2) | 15 (46.9) | 31 (50.8) |
| Symptom duration before enrolment | |||
| ≤10 days | 22 (75.9) | 25 (78.1) | 47 (77) |
| >10 days | 7 (24.1) | 7 (21.9) | 14 (23) |
| Baseline respiratory rate, breaths·min−1 | 19.5±4 | 18.2±3 | 19.2±4 |
| PaO2/FIO2 , mmHg | 280±50 | 310±46 | 296±50 |
| Baseline oxygen support | |||
| None | 0 | 1 (3.1) | 1 (1.6) |
| Low-flow nasal cannula | 16 (55.2) | 16 (50) | 32 (52.5) |
| Venturi mask | 11 (37.9) | 12 (37.5) | 23 (37.7) |
| Non-rebreather mask | 2 (6.9) | 3 (9.4) | 5 (8.2) |
| Treatment with corticosteroids | 27 (93.1) | 27 (84.4) | 54 (88.5) |
| Treatment with remdesivir | 17 (58.6) | 22 (68.7) | 39 (63.9) |
| Treatment with monoclonal antibodies | 7 (25.0) | 8 (24.2) | 15 (24.6) |
|
Daily time in prone position, h·day−1,
median (IQR) |
|||
| Day 1 of follow-up | 3 (0–6) | 0 (0–0) | – |
| Day 3 of follow-up | 4 (0–7) | 0 (0–0) | – |
| Required CPAP helmet | 7 (24.1) | 4 (12.5) | 11 (18.0) |
| Intubated and mechanically ventilated | 4 (13.8) | 0 (0) | 4 (6.5) |
| Death | 2 (7.1) | 1 (3.0) | 3 (4.9) |
| Length of hospital stay, days | 15.2±11.0 | 12.7±7.2 | 13.9±9.2 |
Data are presented as mean±sd or n (%), unless otherwise indicated. BMI: body mass index; COPD: chronic obstructive pulmonary disease; CPAP: continuous positive airway pressure; IQR: interquartile range; PaO2: arterial oxygen tension; FIO2: inspiratory oxygen fraction; PP: prone positioning.