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Table 1 Baseline characteristics of the study population before and after inverse probability of treatment weighting

From: Impact of exposure time in awake prone positioning on clinical outcomes of patients with COVID-19-related acute respiratory failure treated with high-flow nasal oxygen: a multicenter cohort study

Characteristic

Before IPW

After IPWc

Awake-prone positioning

(n = 187)

Non-prone positioning

(n = 148)

Standardized difference

Awake-prone positioning

(n = 186)

Non-prone positioning

(n = 147)

Standardized difference

Demographics

 Age, years, median (p 25–75)

57 (47–66)

66.5 (56.5–75)

− 0.58

60 (49–68)

62 (53–75)

− 0.07

 Female, sex, n (%)

45 (24)

41 (28)

− 0.09

43 (23)

37 (25)

− 0.03

 Body mass index

30 (27.5–33)

30.0 (26.8–33.1)

− 0.04

30.3 (28.4–34)

30 (27–33)

0.04

Comorbidities, n (%)

 Respiratory

22 (12)

22 (15)

− 0.07

24 (13)

19 (13)

0.02

 Cardiovascular

41 (22)

43 (29)

− 0.15

48 (26)

44 (30)

− 0.03

 Renal

8 (4,2)

9 (6)

− 0.10

14 (7.7)

8 (5.6)

− 0.03

 Hepatic

4 (2)

1 (0.6)

0.12

3 (1,6)

3 (2)

− 0.06

 Oncohematologic

2 (1)

13 (9)

− 0.38

6 (3.5)

9 (6)

− 0.05

 Solid neoplasm

2 (1)

4 (2.7)

− 0.12

2 (1)

2 (1.35)

− 0.04

 Immunosuppression

6 (3)

10 (6.7)

− 0.13

10 (5.4)

5 (3.3)

− 0.03

 Neurologic

6 (3)

8 (5.4)

− 0.10

5 (2.5)

4 (2.9)

− 0.04

 Diabetes

40 (21)

43 (29)

− 0.19

55 (29.5)

41 (28)

− 0.04

 Hypertension

62 (33)

80 (54)

− 0.43

70 (37.2)

73 (50)

− 0.07

 Smoking

50 (27)

53 (36)

− 0.20

51 (27.3)

41 (28)

− 0.01

Chronology

 Days from symptom onset to hospital admission, median (p25–75)

8 (6–10)

8.0 (5–10)

0.01

8 (6–10)

9 (5–11)

− 0.05

 Previous days of oxygen therapy, median (p25–75)

1 (0–2)

1 (1–3)

− 0.26

1 (0–3)

1 (0–3)

0.003

Laboratory at admission

 CRP, mg/dl, median (p 25–75)

10.7 (5.1–18)

9.26 (5–17)

− 0.05

9.7 (5–16)

8.6 (5–17)

− 0.002

Respiratory-hemodynamics, and scores at admission

 APACHE score, median (p 25–75)

10 (7–12)

10 (8–13)

− 0.22

10 (6–13)

10 (7–13)

− 0.10

 SOFA score, median (p 25–75)

3 (2–4)

3 (2–4)

0.02

3 (2–4)

3 (2–4)

− 0.05

 CT scored, median (p 25–75)

13 (9–17)

13 (10–15)

0.12

13 (9–17)

13 (10–15)

0.01

 ROX index, median (p 25–75)

6.6 (4.7–11)

6 (4.1–8.3)

0.39

6.3 (4.8–9.5)

5.6 (4.2–8.3)

0.10

Treatments

 Antibiotics, n (%)

150 (80)

133 (90)

− 0.28

158 (85)

128 (87)

− 0.07

 Systemic corticosteroids, n (%)

185 (99)

145 (98)

0.08

184 (99)

146 (99)

0.03

 Light sedation, n (%)

116 (62)

46 (31)

0.65

90 (48)

66 (45)

0.03

 Oxygen therapy previous to ICU-admission (mode)b

1.68

1.71

− 0.07

1.78

1.75

− 0.02

  1. The total number of awake-prone positioning and non-prone positioning patients is slightly different in the post-IPW pseudo-data set as a result of weighting
  2. CRP: C-reactive protein; CT score: computed tomography score; HFNO: high-flow nasal oxygen; LDH: lactate dehydrogenase; PaCO2: CO2 blood pressure; PaO2/FiO2: ratio of pressure of oxygen in arterial blood (PaO2) to the fraction of inspired oxygen (FiO2). SaO2/FiO2: ratio of arterial oxygen saturation to fraction of inspired oxygen
  3. aNumerical variables are expressed as median and percentile 25.75. Dichotomous categorical variables are expressed as n (%). The standardized difference > 0.1 represents an imbalance between the groups
  4. bBefore HFNO, patients received O2 in some of the three following ways: low-flow O2 cannula, Venturi mask, and non-rebreathing mask (see also Table 2). The value represents the mean distribution of the variable between groups
  5. cVariables included in the logistic regression model with awake prone position as the main exposure
  6. dFifty-four patients did not have CT scans at the time of ICU admission. The values were imputed as the mean of each group population
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Critical Care

ISSN: 1364-8535