Table 1 The patients’ characteristics of the included studies (n = 23)

Alptekinoğlu et al. 2021

Turkey

Academic hospital

Pneumonia, extra-pulmonary sepsis, pleural effusion, non-infections pulmonary disease, CHF, ARDS and other

HFNC: 51

Mean

(SD):

57(15)

33/18

Mean

(SD):

256(19)

Mean

(SD):

30(5)

Immunocompromised patients

NIV: 49

Mean

(SD):

58(12)

33/16

Mean

(SD):

270(23)

Mean

(SD):

32(5)

Andino et al.

2020

Spanish

Academic hospital

Community/ hospital-acquired pneumonia, adult respiratory distress, pulmonary embolism and other diagnoses

HFNC: 24

Mean

(SD):

58(19)

13/11

Mean

(SD):

96(29)

Mean

(SD):

35(6)

NR

NIV: 22

Mean

(SD):

61(11)

13/9

Mean

(SD):

95(37)

Mean

(SD):

34(7)

Azoulay et al. 2018

France

24 university-affiliated, 8 non–university-affiliated hospitals

Chronic respiratory diseases, heart failure, liver/kidney diseases

HFNC: 388

Median

(IQR):

64(55–70)

270/118

Median

(IQR):

136(96–187)

NR

Immunocompromised patients

NIV: 388

Median

(IQR):

63(56–70)

147/141

Median

(IQR):

128(92–164)

NR

Bell et al. 2015

Australia

Tertiary referral hospitals

NR

HFNC: 48

Mean

(SD):

72.9(14)

20/28

NR

NR

NR

NIV: 52

Mean

(SD):

72.9(15.1)

24/28

NR

NR

Coudroy et al.

2022

France

Academic hospital

NR

HFNC:

154

Mean

(SD):

62(13)

95/59

Mean

(SD):

148(56)

Mean

(SD):

34(6)

Immunocompromised patients

NIV:

145

Mean

(SD):

65(12)

97/48

Mean

(SD):

147(57)

Mean

(SD):

35(6)

Feng et al. 2020

China

Academic hospital

Community acquired pneumonia,

Hospital acquired pneumonia,

Extrapulmonary sepsis, other

HFNC:40

Mean

(SD):

60(9)

27/13

Mean

(SD):

154(61)

Mean

(SD):

32(5)

NR

SO: 39

Mean

(SD):

55(13)

22/17

Mean

(SD):

142(67)

Mean

(SD):

36(4)

NIV: 37

Mean

(SD):

57(11)

22/15

Mean

(SD):

148(62)

Mean (SD):

39(5)

Frat et al.

2015

France

Academic hospital

Community acquired pneumonia,

Hospital acquired pneumonia,

Extrapulmonary sepsis, aspiration or drowning,

Pneumonia-related to immunosuppression, Other

HFNC:

106

Mean

(SD):

61(16)

75/31

Mean

(SD):

157(89)

Mean

(SD):

36(6)

NR

SO:

94

Mean

(SD):

59(17)

63/31

Mean

(SD):

161(73)

Mean

(SD):

35(5)

NIV:

110

Mean

(SD):

61(17)

74/36

Mean

(SD):

149(72)

Mean

(SD):

34(5)

Frat et al. 2022

France

34 ICUs in France

COVID-19

HFNC: 357

Mean

(SD):

61(12)

250/107

Mean

(SD):

128(31)

Mean

(SD):

35(5)

COVID-19 patients

NIV: 354

Mean

(SD):

61(12)

247/107

Mean

(SD):

132(31)

Mean

(SD):

35(4)

Grieco et al.

2021

Italy

Academic hospital

COVID-19

HFNC:

55

Median

(IQR):

63(55–69)

46/9

Median

(IQR):

102(80–124)

Median (IQR):

34(32–37)

COVID-19 patients

NIV:

54

Median

(IQR):

66(57–72)

42/12

Median

(IQR):

105(83–125)

Median (IQR):

34(31–37)

Jones et al.

2016

New Zealand

A tertiary academic inner-city hospital

NR

HFNC:

165

Mean

(SD):

74.6(15.6)

73/92

NR

NR

NR

NIV:

138

Mean

(SD):

72.2(16.8)

71/67

NR

NR

Lemiale et al.

2015

France

Academic hospital

Sepsis, cardiogenic pulmonary edema, noninfectious pulmonary disease, lung involvement by the underlying disease, large pleural effusion, Pneumocystis pneumonia, miscellaneous, no diagnosis

HFNC:

52

Median

(IQR):

59.3(43–70)

38/14

Median

(IQR):

128(48–178)

NR

Immunocompromised patients

NIV:

48

Median

(IQR):

64.5(53.25–72)

32/16

Median

(IQR):

100 (40–156)

NR

Lemiale et al.

2016

France

Academic hospital

Infection,

Cardiogenic edema,

Opportunistic infection, fungal infection, others

HFNC:

127

Median

(IQR):

64 (53–72)

85/42

NR

NR

Immunocompromised patients

NIV:

226

Median

(IQR):

63 (52–70)

63/163

NR

NR

Liu et al.

2018

China

NR

NR

HFNC:

40

Mean

(SD):

50.85(7.53)

22/18

NR

NR

Immunocompromised patients

NIV:

40

Mean

(SD):

52. 31(6.78)

24/16

NR

NR

Nair et al.

2021

India

ICU in All India Institute of Medical Sciences

COVID-19

HFNC:

55

Median

(IQR):

57(48–65)

44/11

Median

(IQR):105.0 (92.0–139.3)

Median (IQR):34 (26.3–38.5)

COVID-19 patients

NIV:

54

Median

(IQR):

57.5(47–64)

35/19

Median

(IQR):111.2 (89.8–145.0)

Median (IQR):32 (26.0–43.3)

OspinaTascón et al. 2021

Colombia

NR

COVID-19

HFNC:

99

Median

(IQR):

60(50–69)

71/28

Median

(IQR):

104(85–132)

Median (IQR):

32(30–35)

COVID-19 patients

NIV:

100

Median

(IQR):

59(49–67)

63/37

Median

(IQR):

105(85–141)

Median (IQR):

32(30–36)

Perkins et al. 2022

UK

48 acute care hospitals in the UK and Jersey

COVID-19

HFNC:

418

Mean

(SD):

57.6(13.0)

272/146

Median

(IQR): 115.0 (80.9–168.4)

Median (IQR): 33.0 (30.0–36.0)

COVID-19 patients

NIV:

380

Mean

(SD):

56.7(12.5)

260/120

Median

(IQR): 112.5 (80.0–161.3)

Median (IQR): 33.0 (30.0–36.8)

COT:

475

Mean

(SD):

57.6(12.7)

312/163

Median

(IQR): 113.8 (84.8–150.9)

Median (IQR): 33.8 (30.8–36.8)

Qiao et al.

2021

China

University-affiliated hospital

AIS

HFNC:

50

Mean

(SD): 68.7(10.2)

30/20

Mean

(SD):

223.3(17.8)

NR

AIS patients

NIV:

48

Mean

(SD): 70.4(12.4)

30/18

Mean

(SD):

217.3(18.6)

NR

Rittayamai et al. 2015

Thailand

Academic hospital

NR

HFNC: 20

Mean

(SD):

65.6(14.4)

9/11

NR

NR

NR

NIV: 20

Mean

(SD):

63.6(15.7)

6/14

NR

NR

Stephan et al. 2015

France

NR

Cardiothoracic surgery

HFNC:

414

Median

(IQR): 63.8 (62.5–65.2)

273/141

Median

(IQR): 196 (187–204)

Median (IQR): 38.7 (38.1–39.4)

Cardiothoracic surgery patients

NIV:

416

Median

(IQR): 63.9 (62.6–65.2)

278/138

Median

(IQR): 203 (195–212)

Median (IQR): 39.1 (38.4–39.8)

Vourc'h et al. 2019

France

Academic hospital

Atelectasis,

Hemothorax,

Acute colonic pseudo-obstruction, cardiogenic pulmonary edema,

pneumonia,

Pericardial effusion

HFNC:

47

Mean

(SD):

65.8(10.1)

41/6

Mean

(SD):

147.7(30.7)

Mean

(SD):

40.5(3.8)

Cardiothoracic surgery patients

NIV:

43

Mean

(SD):

67.6(9.4)

36/7

Mean

(SD):

131.5(27.7)

Mean

(SD):

39.8(4.5)

Wang et al. 2018

China

NR

NR

HFNC:

28

Mean

(SD):

63.8(12.5)

16/12

NR

Mean

(SD): 29.1(2.8)

NR

NIV:

28

Mean

(SD):

62.4(13.3)

17/11

NR

Mean

(SD): 30.2(3.6)

Zhao et al.

2019

China

University-affiliated hospitals

NR

HFNC:

80

Mean

(SD):

56.32(5.23)

42/38

Mean

(SD):

137.5(34.2)

Mean

(SD):

37.36(3.74)

NR

NIV:

80

Mean

(SD):

55.86(6.35)

44/36

Mean

(SD):

142.9(32.4)

Mean

(SD):

38.09(4.05)

Zeng et al.

2019

China

NR

NR

HFNC:

62

Mean

(SD):

56.94(9.46)

32/30

Mean

(SD):

164.4(21.5)

NR

NR

NIV:

62

Mean

(SD):

57.23(9.73)

35/27

Mean

(SD):

163.9(21.8)

NR