Table 2 Summary of subgroup analysis results
Study | Outcome | Subgroup | Numbers | MD(RR/OR) | Heterogeneity | p value | |
|---|---|---|---|---|---|---|---|
Cheema 2023 [21] | Intubation rate | type of respiratory support | higher level of respiratory support | 4 RCT(765/756) | RR 0.82[0.71, 0.93] | 0% | 0.29 |
conventional oxygen therapy | 9 RCT(450/411) | RR 1.07[0.66, 1.73] | 0% | ||||
enrollment location | non-ICU | 7 RCT(394/355) | RR 0.88[0.44, 1.76] | 0% | 0.87 | ||
ICU | 4 RCT(788/773) | RR 0.83[0.73, 0.95] | 0% | ||||
Mortality | type of respiratory support | higher level of respiratory support | 4 RCT(810/799) | RR 0.92[0.76,1.10] | 0% | 0.64 | |
conventional oxygen therapy | 8 RCT(405/368) | RR 1.14[0.47,2.75] | 0% | ||||
enrollment location | ICU | 4 RCT(808/773) | RR 0.91[0.75,1.10] | 0% | 0.75 | ||
non-ICU | 7 RCT(394/355) | RR 0.81[0.41,1.59] | 0% | ||||
Li 2022 [22] | Intubation rate | type of respiratory support | higher level of respiratory support | 3 RCT(605/604) | RR 0.83[0.71, 0.97] | 0% | 0.88 |
conventional oxygen therapy | 8 RCT(405/368) | RR 0.87 [0.45, 1.69] | 0% | ||||
enrollment location | ICU | 3 RCT(583/578) | RR 0.83 [0.71, 0.97] | 0% | 0.86 | ||
non-ICU | 7 RCT(394/355) | RR 0.88 [0.44, 1.76] | 0% | ||||
Mortality | type of respiratory support | higher level of respiratory support | 3 RCT(605/604) | RR 1.23 [0.54, 2.80] | 32% | 0.90 | |
conventional oxygen therapy | 8 RCT(405/368) | RR 1.14 [0.47, 2.75] | 0% | ||||
enrollment location | ICU | 3RCT(583/578) | RR 0.90 [0.72, 1.13] | 0% | 0.77 | ||
non-ICU | 7 RCT(394/355) | RR 0.81 [0.41, 1.59] | 0% | ||||
ICU length of stay | type of respiratory support | higher level of respiratory support | 3 RCT(401/441) | MD −0.53[−1.82, 0.75] | 0% | – | |
conventional oxygen therapy | 3 RCT(68/67) | MD 0.76[−0.62, 2.13] | 0% | – | |||
enrollment location | ICU | 3 RCT(583/578) | MD 0.34[−0.77, 1.45] | 0% | – | ||
non-ICU | 2 RCT(57/54) | MD −0.99[−2.69, 0.71] | 0% | – | |||
Hospital length of stay | type of respiratory support | higher level of respiratory support | 3 RCT(605/604) | MD −0.35[−1.53, 0.83] | 39% | – | |
conventional oxygen therapy | 6 RCT(252/216) | MD 1.15[0.26, 2.05] | 0% | – | |||
enrollment location | ICU | 2 RCT(553/548) | MD 0.22[−1.55, 2.00] | 26% | – | ||
non-ICU | 6 RCT(268/233) | MD 1.16[0.27, 2.05] | 0% | – | |||
Kang 2022 [24] | Intubation rate | type of respiratory support | conventional oxygen therapy | 4 RCT(51/77) | OR 1.04[0.22, 4.87] | 0% | 0.51 |
HFNC/NIV | 5 RCT(1058/1102) | OR 0.60[0.39, 0.93] | |||||
daily median duration | >8H | 5 RCT(519/568) | OR 0.47[0.25, 0.88] | 65.5% | 0.09 | ||
<8H | 8 RCT(1277/1264) | OR 0.85[0.65, 1.12] | |||||
Mortality | type of respiratory support | conventional oxygen therapy | 4 RCT(120/185) | OR 0.37[0.17, 0.81] | 55.1% | 0.14 | |
HFNC/NIV | 5 RCT(1052/1080) | OR 0.76[0.46, 1.26] | |||||
daily median duration | >8H | 5 RCT(513/546) | OR 0.65[0.31, 1.34] | 0% | 0.49 | ||
<8H | 7 RCT(1231/1230) | OR 0.85[0.65, 1.11] | |||||
Lee 2022 [26] | Mortality | type of respiratory support | Nasal cannula or facial mask | 3 RCT(183/165) | RR 1.13[0.31, 5.70] | 0% | 0.61 |
HFNC/NIV | 5 RCT(1036/1020) | RR 0.91[0.78, 1.05] | |||||
type of respiratory support | Nasal cannula or facial mask | 6 non-randomized studies(700/609) | RR 0.57[0.48, 0.67] | 0% | 0.40 | ||
HFNC/NIV | 6 non-randomized studies(405/857) | RR 0.47[0.31, 0.71] | |||||
Intubation rate | type of respiratory support | Nasal cannula or facial mask | 2 RCT(57/43) | RR 1.00[0.28, 3.63] | 0% | 0.74 | |
HFNC/NIV | 5 RCT(1036/1020) | RR 0.80[0.72, 0.90] | |||||
type of respiratory support | Nasal cannula or facial mask | 5 non-randomized studies(640/506) | RR 0.74[0.41, 1.33] | 0% | 0.53 | ||
HFNC/NIV | 6 non-randomized studies(411/879) | RR 0.60[0.42, 0.85] | |||||
Weatherald 2022 [27] | Intubation rate | daily median duration | ≥5 h | 3 RCT(457/448) | RR 0.78[0.66, 0.93] | 0% | 0.72 |
<5 h | 7 RCT(489/480) | RR 0.92[0.76, 1.12] | |||||
median baseline oxygen saturation to fraction of inspired oxygen (SpO2:FiO2) | SpO2:FiO2 < 150 | 2 RCT(421/409) | RR 0.77[0.64, 0.92] | 0% | 0.85 | ||
SpO2:FiO2 ≥ 150 | 10 RCT(1151/1107) | RR 0.92[0.77, 1.10] | |||||
type of respiratory support | high flow or NIV | 9 RCT(805/778) | RR 0.81[0.71, 0.92] | 0% | 0.74 | ||
mixed | 3 RCT(187/182) | RR 1.07[0.49, 2.34] | |||||
low flow | 3 RCT(219/192) | RR 1.18[0.63, 2.19] | |||||
enrollment location | location mixed | 6 RCT(588/576) | RR 0.81[0.69, 0.95] | 0% | 0.83 | ||
ICU | 4 RCT(292/275) | RR 0.86[0.69, 1.08] | |||||
in ward | 4 RCT(331/301) | RR 0.96[0.43, 2.13] | |||||
Economic Co-operation and Development in 2021 | low or middle income countries | 3 RCT(291/274) | RR 0.69[0.55, 0.87] | 0% | 0.83 | ||
High income countries | 11 RCT(920/878) | RR 0.89[0.77, 1.04] | |||||
Wang 2022 | Intubation rate | SpO2/FiO2 ratio at baseline | SpO2/FiO2 > 235 mmHg | 4 RCT(310/288) | RR 0.93[0.40, 2.19] | 0% | – |
SpO2/FiO2 ≤ 235 mmHg | 4 RCT(1021/1005) | RR 0.80[0.71, 0.90] | 0% | – | |||
Mortality | SpO2/FiO2 ratio at baseline | SpO2/FiO2 > 235 mmHg | 4 RCT(214/196) | RR 1.32[0.44, 2.99] | 0% | – | |
SpO2/FiO2 ≤ 235 mmHg | 4 RCT(1021/1005) | RR 0.91[0.78, 1.06] | 0% | – | |||
Cao 2023 [29] | Intubation rate | Oxygen supply | HFNC | 4 RCT(1021/1005) | OR 0.69[0.58, 0.83] | 0% | – |
Mortality | Oxygen supply | HFNC | 4 RCT(1144/1100) | OR 0.86[0.79, 1.05] | 0% | – | |
Peng 2023 [30] | Intubation rate | daily median duration | >8H | 9 RCT(1218/1172) | OR 0.76[0.63, 0.91] | 0% | 0.18 |
<8H | 4 RCT(456/417) | OR 0.59[0.42, 0.82] | 0% | ||||
enrollment location | ICU | 6 RCT(1064/1022) | OR 0.73[0.61, 0.88] | 0% | 0.61 | ||
non-ICU | 7 RCT(610/567) | OR 0.72[0.61, 0.84] | 0% | ||||
type of respiratory support | conventional oxygen therapy | 9 RCT(450/411) | OR 1.05[0.59, 1.86] | 0% | 0.12 | ||
HFNC/NIV | 6 RCT(1026/1000) | OR 0.65[0.54, 0.78] | 0% | ||||