| Bias | Author's judgement | Support for judgement |
| Confounding |
Serious |
Baseline severity of COVID-19 and site effect were neither reported, controlled for, nor demonstrated not to be confounders. There were no imbalances in the other important variables not included in the model. |
| Selection of participants into the study |
Serious |
Patients who received therapeutic anticoagulation specifically for a thrombotic indication were excluded from this study. Some of those in the therapeutic group were treated later than the prophylaxis group and therefore may have been sicker at the time of treatment. Due to the time-varying exposure variable, they conducted a sensitivity analyses that defined for dosage at time of admission. |
| Intervention classification |
Low |
Abstracted from hospital medical records. Patients were assigned to the therapeutic group if they preemptively received a therapeutic dosage of either medication at any time or the prophylaxis group if they only received prophylaxis for the duration of their inpatient stay. Generic name, frequency and dosage reported. It is unclear how long treatment was given, but assumption is until death or discharge from hospital. |
| Deviation from intended intervention |
Serious |
Lopinavir/ritonavir administration was not balanced between groups. The use of other antivirals was not reported. The regression model adjusted for antibiotic use. |
| Missing data |
Moderate |
23/374 (6%) total excluded from the adjusted model due to missing variables; the proportion missing per group was not reported. |
| Measurements of outcomes |
Low |
Mortality is an objective outcome. |
| Selection of the reported results |
Moderate |
No study registration, protocol or statistical analysis plan was reported. The in-hospital mortality outcome and analyses are clearly defined in the Methods section; and these results are presented for the total adjusted sample along with one subgroup analysis and one sensitivity analysis. |