Characteristics of Included Studies
| Study | Nation of Origin | COVID-19 Comparison Groups | Study Design | Sample Size N |
|---|---|---|---|---|
| Mo et al.4 | China | Refractory vs Non-refractory | Retrospective cohort | 155 |
| Wu et al.6 | China | ARDS vs No ARDS | Retrospective cohort | 201 |
| Zhou et al.7 | China | Non-survivor vs Survivor | Retrospective cohort | 191 |
| Zhang et al.8 | China | Severe vs Non-severe COVID-19 | Retrospective cohort | 140 |
| Du et al.9 | China | Non-survivor vs Survivor | Prospective cohort | 179 |
| Li et al.10 | China | Non-survivor vs Survivor | Retrospective cohort | 102 |
ARDS, acute respiratory distress syndrome; vs, versus.