Note: The risk of bias by domain corresponds to the highest risk of bias among outcomes by domain.
The overall risk of bias corresponds to the overall highest risk of bias assessed among outcomes.
Bias | Author's judgement | Support for judgement |
Randomization |
Low |
Quote: "Eligible participants were randomized using an internet-based system with allocation concealment."
Comment: Allocation sequence random. Allocation sequence concealed. Imbalances in baseline characteristics appear to be compatible with chance. |
Deviations from intervention |
Some concerns |
Quote: "Open-label"
Comment: Unblinded study (participants and personnel/carers). Deviations from intended intervention arising because of the study context: Co-interventions of interest: there was very limited information on administration of corticosteroids and biologics, there was an "introduction of Dexamethasone and Tocilizumab as standard care in June 2020 and January 2021, respectively". Antivirals were not reported. Cross-over: 15.3% of participants randomized to CPAP received HFNO, 11.5% of participants randomized to HFNO received CPAP, 8.4% of participants randomized to conventional oxygen therapy received CPAP, 7.6% received HFNO, and 7.6% received both CPAP and HFNO. These deviations were not balanced and could affect the outcome. Nevertheless, this domain was rated as some concern as it is impossible to distinguish deviation because of trial context and deviation because of intervention effect. Our analysis for the binary outcomes are intention-to-treat analyses. This method was considered appropriate to estimate the effect of assignment to intervention. Risk assessed to be some concerns for the outcomes: Adverse events. Serious adverse events. |
Missing outcome data |
Low |
Comment: 1272 participants randomized; 1272 participants analyzed.
Data available for all participants randomized. Risk assessed to be low for the outcomes: Adverse events. Serious adverse events. |
Measurement of the outcome |
Some concerns |
Comment: Method of measuring the outcome probably appropriate.
Measurement or ascertainment of outcome probably does not differ between groups. Unblinded study (outcome assessor) ADVERSE and SERIOUS ADVERSE EVENTS The authors reported on adverse events and serious adverse events that may contain both clinically- and laboratory-detected events, which can be influenced by knowledge of the intervention assignment, but is not likely in the context of the pandemic. Risk assessed to be some concerns for the outcomes: Adverse events. Serious adverse events. |
Selection of the reported results |
Low |
Comment: The protocol, statistical analysis plan, and prospective trial registry were available.
Outcomes were pre-specified. Results were not selected from multiple outcome measurements or analyses of the data. Trial analyzed as pre-specified. Risk assessed to be low for the outcomes: Adverse events. Serious adverse events. |
Overall risk of bias |
Some concerns |