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: “All patients who met the inclusion criteria and presented no exclusion criteria were randomly split into three groups”
Comment: Allocation sequence probably random. No information on allocation concealment |
| Deviations from intervention |
Some concerns |
Comment: No information on blinding (participants and personnel/carers) Deviations from intended intervention arising because of the study context: 4 patients in the UFH (control) arm were withdrawn from the study due to adverse reactions and switched to LMWH (treatment). No information on administration of co-interventions of interest: antivirals, biologics and corticosteroids. 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. Participants were not analyzed according to their randomized groups for the outcome. Of note, 4 participants randomized to the control group were withdrawn from the study and received the intervention. No information on which group they were analyzed in. Nevertheless, we considered the analysis to be probably appropriate to estimate the effect of assignment to intervention. Risk assessed to be some concerns for the outcomes: Mortality (D28). Adverse events. Serious adverse events. |
| Missing outcome data |
Low |
Comment: 126 participants randomized; 122 participants analyzed.
Data available for all or nearly all participants randomized. Risk assessed to be low for the outcomes: Mortality (D28). 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. Unclear blinding (outcome assessor). MORTALITY Observer-reported outcome not involving judgement. Risk assessed to be low for the outcomes: Mortality (D28). 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 |
Some concerns |
Comment: The protocol, statistical analysis plan and registry were not available
ADVERSE AND SERIOUS ADVERSE EVENTS 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 outcome: Adverse events. Serious adverse events. MORTALITY Outcome was not pre-specified in the [protocol/SAP/registry], however, we do not consider the reporting of this outcome to be selective since mortality should be reported even if not planned. Results were probably 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). |
| Overall risk of bias |
Some concerns |