| Bias | Author's judgement | Support for judgement |
| Confounding |
Moderate |
Comment: The confounders of interest (age, sex, comorbidities, severity) were controlled for in the propensity score model (see “Statistical Analysis” section; see Table 1 for baseline differences in confounders). See “Statistical Analysis” section for measures used by the authors. |
| Selection of participants into the study |
Moderate |
Comment: Patients are classified as HCQ if they use HCQ within 48 hours since admission, but outcomes occurring in the first 48 hours may preclude use of HCQ. the authors used methods to randomly assigned to one of the two groups at the time of the even |
| Intervention classification |
Low |
Comment:Data were collected from electronic health records, and treatment groups were classified using clearly defined criteria. |
| Deviation from intended intervention |
Low |
Comment: Some imbalance in co-intervention |
| Missing data |
Low |
Comment: 181 included/181 analyzed. Risk assessed to be low for the outcomes: Mortality. |
| Measurements of outcomes |
Low |
Comment: Objective outcomes not involved judgment transfer to admission ICU or death |
| Selection of the reported results |
Moderate |
Comment: The outcomes and analyses are clearly defined in the Methods section. Planned subgroup/sensitivity analysis results are reported. There is no a-priori registered protocol or statistical analysis plan available. Risk assessed to be moderate for the outcomes: Mortality. |