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: “The randomization was done by using block randomization method with varying block sizes by an independent statistician. The allocation concealment was done by using Sequentially Numbered Opaque Sealed Envelopes (SNOSE) method.”
Comment: Allocation sequence random. Allocation sequence concealed. |
| Deviations from intervention |
Some concerns |
Quote: “Open label study”
Comment: Unblinded study (participants and personnel/carers). No participant cross-over. No information on administration of co-interventions of interest: antivirals, corticosteroids, biologics were reported. Hence, no information on whether deviations arose because of the trial context. Data for the binary outcomes were analyzed using intention-to-treat analysis. This method was considered appropriate to estimate the effect of assignment to intervention. Participants were analyzed according to their randomized groups for the time-to-event outcome. Of note, 1 vs 1 participants were excluded from the analysis post-randomization due to protocol violation (became negative on RT-PCR before transfusion). This is a post-randomization exclusion of ineligible participants and was considered appropriate to estimate the effect of assignment to intervention for this time-to-event outcome. Risk assessed to be some concerns for the outcomes: Mortality (D28). Time to death. Adverse events. Serious adverse events. |
| Missing outcome data |
Low |
Comment: 31 participants randomized; 29 participants analyzed.
Data not available for all or nearly all participants randomized. No evidence that the result is not biased. Reason: One patient in each arm excluded due to change in eligibility status (negative RT-PCR conversion after randomization but prior to treatment) which is unrelated to the outcome. Missingness could not depend on the true value of the outcome. Risk assessed to be low for the outcomes: Mortality (D28). Time to death. 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) Mortality is an observer-reported outcome not involving judgement. Risk assessed to be low for the outcome: Mortality. Time to death. The authors reported on adverse events that contain clinically-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 |
Some concerns |
Comment: Neither the protocol nor the statistical analysis plan was available at time of assessment. The prospective registry was available and specified mortality at day 28 as an outcome.
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 outcome: Mortality (D28). Time to death and safety outcomes were not listed in the registry No information on whether the result was selected from multiple outcome measurements or analyses of the data. Trial probably not analyzed as pre-specified. Risk assessed to be some concerns for the outcomes: Time to death. Adverse events. Serious adverse events. |
| Overall risk of bias |
Some concerns |