Table 2 Baseline characteristics and outcomes according to subgroups of silent and dyspneic hypoxemia

Characteristics

Assigned to APP arm—no. (%)

58 (49.5)

158 (50.5)

–

–

Age, median (IQR)

59 (47–73)

59 (49–71)

–

–

Female sex—no. (%)*

58 (50)

200 (64)

–

–

Body mass index ^a, median (IQR)

29.0 (27.2–32.4)

28.9 (27.4–32.5)

–

–

Days from symptoms onset to hospital admission, median (IQR)

8 (7–9)

8 (7–10)

–

–

Hours from admission in hospital to enrollment in study, median (IQR)

16 (9–27)

14 (9–24)

–

–

Hours from HFNC to enrollment, median (IQR)

8 (4–20)

9 (5–12)

–

–

Respiratory rate at enrollment, median (IQR)*

25.0 (21.0–27.0)

26.0 (23.0–28.0)

–

–

SpO₂:FiO₂ ratio at enrollment, median (IQR)

156 (93–160)

132 (92–160)

–

–

Lung ultrasound score ^b, median (IQR)*

18 (15–20)

19 (16–22)

–

–

D-dimer mg/dL, median (IQR)

1.1 (0.8–1.4)

1.2 (0.9–1.7)

–

–

Coexisting illness ^c

87 (74)

217 (69)

–

–

Use of glucocorticoids for treatment of Covid-19—no. (%)

101 (86)

265 (85)

–

–

Highest treating location*

–

–

 Intermediate care unit—no. (%)

110 (94)

224 (72)

–

–

 Intensive care unit—no. (%)

7 (6)

89 (28)

–

–

Outcomes

Intubation at day 28– no. (%)

29/117 (25)

128/313 (41)

0.60 (0.43–0.85)

0.004

Mortality at day 28– no. (%)

 All patients

27/117 (23)

123/313 (39)

0.58 (0.41–0.84)

0.001

 Patients with IMV

21/29 (72)

86/128 (67)

1.07 (0.83–1.39)

0.56

Treatment success at day 28 (alive without intubation)—no. (%)

82/117 (70)

148/313 (47)

1.76 (1.31–2.37)

< 0.001

Days of HFNC in patients who had treatment success, median (IQR)

0.60

Days from study enrollment to intubation in patients with IMV, median (IQR)

0.88

Days of IMV, median (IQR)

0.37

Hospital LOS, median (IQR)

0.66