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: “Computer generated randomization. Sequentially numbered, sealed, opaque envelopes.” (Registry)
Comment: Allocation sequence random. Allocation sequence concealed. |
| 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: No information on administration of co-interventions of interest: biologics, antivirals and corticosteroids. Hence, no information on whether deviations arose because of the trial context. Five patients in the non-rebreather mask group were changed to HFNC. This deviation was 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. Data for the outcome were analyzed using intention-to-treat analysis. This method was considered appropriate to estimate the effect of assignment to intervention. Risk assessed to be some concerns for the outcomes: WHO score 7 and above (D28). |
| Missing outcome data |
Low |
Comment: 60 participants randomized; 60 participants analyzed.
Data available for all participants randomized. Risk assessed to be low for the outcomes: WHO score 7 and above (D28). |
| Measurement of the outcome |
Low |
Comment: Method of measuring the outcome probably appropriate.
Measurement or ascertainment of outcome probably does not differ between groups. WHO SCORE 7 AND ABOVE For WHO score 7 and above, we consider that the assessment cannot possibly be influenced by knowledge of intervention assignment. Risk assessed to be low for the outcomes: WHO score 7 and above (D28). |
| Selection of the reported results |
Low |
Comment: The trial registry were available (dated 2021-01-29).
Outcome 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: WHO score 7 and above (D28). |
| Overall risk of bias |
Some concerns |