Introduction: High-flow nasal cannula oxygen (HFNC) and non-invasive ventilation (NIV) have been widely used in patients with acute hypoxic respiratory failure (AHRF) due to coronavirus disease 2019 (COVID-19). However, the impact of HFNC vs. NIV on clinical outcomes of COVID-19 is uncertain. Therefore, we performed this meta-analysis to evaluate the effect of HFNC vs. NIV in COVID-19-related AHRF.Methods: Several electronic databases were searched through February 10, 2022, for eligible studies comparing between HFNC and NIV in COVID-19-related AHRF. Our primary outcome was intubation. The secondary outcomes were mortality, length of hospital stay (LOS), and PaO2/FiO2 ratio changes. Pooled risk ratio (RR) and mean difference (MD) with the corresponding 95% confidence intervals (CIs) were obtained using a random-effect model. Prediction intervals (PI) were calculated to indicate the variance in outcomes that would be expected if new studies were conducted in the future.Results: Nineteen studies involving 3606 subjects (1880 received HFNC and 1726 received NIV) were included. There were no differences in intubation (RR 1.01, 95% CI 0.85-1.20, P=0.89) or LOS (MD 0.38 days, 95% CI -0.61, 1.37, P=0.45) between groups with consistent results on the subgroup of RCTs. Mortality was lower in NIV (RR 0.81, 95% CI 0.66-0.98, P=0.03). However, PI was 0.41-1.59, and subgroup analysis of RCTs showed no difference in mortality between groups. There was a greater improvement in PaO2/FiO2 ratio with NIV (MD 22.80, 95% CI 5.30-40.31, P=0.01).Conclusions: Our study showed that despite the greater improvement in PaO2/FiO2 ratio with NIV, the intubation and length of hospital stay were similar between HFNC and NIV. Although mortality was lower with HFNC than NIV, the prediction interval included the null value, and there was no difference in mortality between HFNC and NIV on a subgroup of RCTs. Future large-scale RCTs are necessary to prove our findings.
High-Flow Nasal Cannula Oxygen versus Non-Invasive Ventilation in Subjects with COVID-19: A Systematic Review and Meta-analysis of Comparative Studies