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 list was created using a computer-generated code, which was managed by a staff member who had no role in the study.”
Comment: Allocation sequence random. Allocation sequence concealed. Imbalances in baseline characteristics appear to be compatible with chance |
| Deviations from intervention |
Low |
Quote: “double-blind, randomized, placebo-controlled trial”
Comment: Blinded study (patients and physicians). ”The vitamin D3 and placebo solutions were identical in color, taste, smell, consistency, and container. Both were prepared by the pharmacy unit of Clinical Hospital and labeled by a staff member who did not participate in the study. Allocation blindness was kept until the final statistical analysis.” Data were not analyzed according to their randomized groups for the outcome. Of note, 1 vs 2 participants were excluded from the analysis post-randomization because they withdrew consent. This method was considered inappropriate to estimate the effect of assignment to intervention for this time-to-event outcome. There was probably no substantial impact of failure to analyze participants according to their randomized groups Risk assessed to be low for the outcomes: Mortality (D28). Time to clinical improvement. Adverse events. |
| Missing outcome data |
Low |
Comment: 240 patients randomized; 237 patients analyzed.
Data available for all or nearly all participants.
No evidence that the result is not biased. Risk assessed to be low for the outcomes: Mortality (D28).Time to clinical improvement. Adverse events. |
| Measurement of the outcome |
Low |
Comment: Method of measuring the outcome probably appropriate.
Measurement or ascertainment of outcome probably does not differ between groups. Comment: Blinded study (outcome assessor). Risk assessed to be low for the outcomes: Mortality (D28). Time to clinical improvement. Adverse events. |
| Selection of the reported results |
Some concerns |
Comment: Neither the protocol nor the statistical analysis plan was available. The registry was available and utilized.
Mortality was registered as reported. Result was not selected from multiple outcome measurements or analyses of the data. Trial analyzed as pre-specified. Risk assessed to be low for outcome: Mortality (D28). Adverse events were not an outcome specified in the registry. 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. Time to clinical improvement was pre-specified as "lenghts of hospitalisation, combined with death. The published report split those outcomes and and presented those separately Trial probably not analyzed as pre-specified. Risk assessed to be some concerns for the outcome: Adverse events.Time to clinical improvement |
| Overall risk of bias |
Some concerns |