Table 2 Confidence assessment in the risk ratio of each comparison and outcome
| Â | Risk of bias across studies | Imprecision | Heterogeneity | Indirectness | Publication bias | Incoherence | Confidence in relative risk of the event |
|---|---|---|---|---|---|---|---|
Short-term mortality | |||||||
  HFNO vs SOT | Undetected | Major concerns (a) 95% CI (0.66–1.20) | No concerns 95% PI (0.47–1.70) | Low | Not suggested | Some concerns P=0.07* | Low |
  NIV vs SOT | Undetected | No concern 95% CI (0.61–0.95) | Major concerns (b) 95% PI (0.42–1.39) | Low | Not suggested | No concerns P=0.05* | Low |
  IMV vs SOT | Undetected | Major concerns (a) 95% CI (0.57–1.78) | No concerns 95% PI (0.45–2.29) | Low | Not suggested | Major concerns(c) P= 0.01** | Very low |
  HFNO vs IMV | Undetected | Major concerns (a) 95% CI (0.47–1.65) | No concerns 95% PI (0.37–2.10) | Low | Not suggested | Major concerns(c) P=0.01** | Very low |
  NIV vs IMV | Undetected | Major concerns (a) 95% CI (0.45–1.27) | No concerns 95% PI (0.34–1.65) | Low | Not suggested | Major concern(c) P= 0.01** | Very low |
  NIV vs HFNO | Undetected | Major concerns (a) 95% CI (0.61–1.20) | No concern 95% PI (0.44–1.67) | Low | Not suggested | Major concern(c) P=0.01* | Very low |
Endotracheal intubation | |||||||
  HFNO vs SOT | Undetected | Some concerns 95% CI (0.61–1.11) | Some concerns 95% PI (0.41–1.64) | Low | Not suggested | No concern P= 0.50* | Moderate |
  NIV vs SOT | Undetected | No concern 95% CI (0.51–0.79) | Major concerns (b) 95% PI (0.33–1.22) | Low | Not suggested | No concern P= 0.85* | Low |
  NIV vs HFNO | Undetected | Some concerns 95% CI (0.56–1.06) | Some concerns 95% PI (0.38–1.56) | Low | Not suggested | No concern P=0.24* | Moderate |