| Bias | Author's judgement | Support for judgement |
| Confounding |
Serious |
"Comment: The following review confounders : Age, Gender, Comorbidities (all except obesity), Severity were controlled for in the regression model. Review confounders not particularly important in this study: ethnicity, socio-economic status, temporal effects were not controlled for. As IVIG was administered after a certain period since admission and some patients started IVIG quite late >7 days since admission (see Table 7), time-varying confounding variables should be controlled for and were not." |
| Selection of participants into the study |
Serious |
Quote: "In-hospital treatment 72 hours" Comment: Patient's discharged (or possibly died) less than 72 hours post admission were excluded. Start of follow up and start of treatment is not at the same moment for some patients. There is a risk of immortal time bias. |
| Intervention classification |
Low |
Quote: "We designed the data collection form, which includes the demographic, clinical, treatment, laboratory data and prognosis were extracted from electronic medical records. Detailed clinical data before and after prescription IVIG, and the data at the corresponding time of the same period in non-IVIG group were collected, respectively. Whether and when to use IVIG, dosage and course were decided by the doctors in charge. Comparison was conducted according to whether IVIG was used or not". Comment: Data were collected from electronic medical records. Treatment groups were classified using defined criteria. |
| Deviation from intended intervention |
NI |
Comment: The information reported is inadequate to assess whether there are deviations from the intended intervention beyond what would be expected in usual practice. No data is provided related to review co-interventions administered. |
| Missing data |
Low |
Quote: “13 patients excluded due to missing data” See Figure 1. Comment: Data available for more than 95% of participants. Risk assessed to be low for outcome: Time to death |
| Measurements of outcomes |
Low |
Comment : Outcome assessors were likely aware of the intervention received however the outcome is an objective measure (60 day mortality) |
| Selection of the reported results |
Moderate |
Comment: The outcomes and analyses are clearly defined in the Methods section. There is no a-priori registered protocol or statistical analysis plan available. Risk assessed to be low for the outcomes: 60 day mortality |