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 |
Some concerns |
Quote: "The patients were randomly divided into 2 groups: a standard treatment group (control group) and a standard treatment plus umbilical cord mesenchymal stem cell infusion group (hUC-MSC group)."
Quote from registry: "the clinical research staff will obtain the random sequence number automatically generated by the random number generator (SPSS 21.0, SPSS Inc., Chicago, IL, USA) and number it sequentially in an opaque envelope." Comment: Allocation sequence random. Unclear allocation concealment (No information on sealed envelopes). |
| Deviations from intervention |
Some concerns |
Comment: Unblinded study (participants and personnel/carers).
Deviations from intended intervention arising because of the study context: No participant cross-over. The n/N per arm related to antiviral and corticosteroid co-interventions are provided. No information on co-intervention administration of biologics. Hence, no information on whether deviations arose because of the trial context. 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: Mortality (D28). Clinical improvement (D28). WHO score 7 and above (D28). |
| Missing outcome data |
Low |
Comment: 41 participants randomized, 41 participants analyzed.
Data available for all participants randomized. Risk assessed to be low for outcomes: Mortality (D28). Clinical improvement (D28). WHO score 7 and above (D28). |
| 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 Mortality is an observer-reported outcome not involving judgement. Risk assessed to be low for the outcomes: Mortality (D28). 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). CLINICAL IMPROVEMENT Clinical improvement requires clinical judgement and could be affected by knowledge of intervention receipt, but it not considered likely to in the context of a pandemic. Risk assessed to be some concerns for the outcomes: Clinical improvement (D28). |
| Selection of the reported results |
Some concerns |
Comment: Protocol and statistical plan not available. The trial registry was available but retrospective (dated April 2nd, 2020).
No information on whether the result was selected from multiple outcome measurements or analyses of the data. No information on whether the trial was analyzed as pre-specified. Risk assessed to be some concerns for the outcomes: Mortality (D28). Clinical improvement (D28). WHO score 7 and above (D28). |
| Overall risk of bias |
Some concerns |