2. Summary of characteristics of included studies.
| Study (design) | Country | Participant age (mean) | Setting | Intervention type (dose) | Comparator | All‐cause mortality | Necessity for additional respiratory support | Follow‐up time (mean days) | Total participants allocated | Intervention group participants (anticoagulant) |
| Ayerbe 2020 (Retrospective cohort) | Spain | 67 | Hospitala | Heparin (NR) | NA | OR 0.42 (95% CI 0.26 to 0.66) P < 0.001, in favour of intervention group | NR | 8 | 2075 | 1734 |
| Liu 2020 (Retrospective cohort) | China | 72 | ICU (intervention) vs hospital ward (comparator) | Heparin (NR) | NA | Unadjusted OR 1.66, 95% CI 0.76 to 3.64 | NR | NR | 154 | 61 |
| Paranjpe 2020 (Retrospective cohort) | USA | NR | Hospitala | Treatment dose anticoagulation | NA | In‐hospital mortality: intervention 22.5% versus comparator 22.8% In subgroup who required mechanical ventilation: intervention 29.1% versus comparator 62.7% (adjusted HR 0.86, 95% CI 0.82 to 0.89; 395 participants, P < 0.001) |
NR | NR | 2773 | 786 |
| Russo 2020 (Retrospective cohort) | Italy | 67 | Hospitala | DOACS (NR) in 18 participants and VKA (NR) in 8 participants | NA | RR 1.15 (95% CI 0.29 to 2.57), P = 0.995 | NR | NR | 192 | 26 |
| Shi 2020 (Retrospective cohort) | China | 69 | Hospitala | LMWH | NA | Reported no deaths in both groups | NR | NR | 42 | 21 |
| Tang 2020 (Retrospective cohort) | China | 65 | Hospitala | UFH (10,000 to 15,000 IU/d in 5 participants and LMWH (40 mg/d to 60 mg/d) in 94 participants | NA | No difference (general mortality): (adjusted OR 1.64, 95% CI 0.92 to 2.92; 449 participants) Subgroup analysis: participants with SIC score of ≥ 4(unadjusted OR 0.37, 95% CI 0.15 to 0.90; 97 participants) Participants with D‐dimer > 6 times the ULN (unadjusted OR 0.44, 95% CI 0.22 to 0.86; 161 participants) |
NR | 28 | 449 | 99 |
| Trinh 2020 (Retrospective cohort) | USA | 59 | ICU | UFH 15 IU/kg/h; or enoxaparin 1 mg/kg twice or once daily; or apixaban 10 mg (if no prior anticoagulation) or 5 mg (if prior anticoagulation) twice dailyb | UFH 5000 IU two to three times daily; or enoxaparin 40 mg twice or once daily; or apixaban 2.5 mg or 5 mg twice dailyb |
Reduction in all‐cause mortality (adjusted HR 0.21, 95% CI 0.10 to 0.46) and a lower absolute rate of death in the therapeutic group (34.2% versus 53%) | NR | 35 | 244 | 161 |
| Total | China: 3 Italy: 1 Spain: 1 USA: 2 |
‐ | ‐ | ‐ | ‐ | 6 studies considered mortality; 1 study did not report mortality data |
No study considered additional respiratory support | 8 to 35 (3 studies) | 5929 | 2888 |
| CI: confidence interval; DOACS: direct oral anticoagulants; GFR: glomerular filtration rate;HR: hazard ratio; ICU: intensive care units;LMWH: low molecular weight heparin; NA: no anticoagulation; NR: not reported; NRS: non‐randomised study;OR: odds ratio; RR: risk ratio; SIC: sepsis‐induced coagulopathy; UFH: unfractionated heparin; VKA: vitamin K antagonist | ||||||||||
aHospital: includes intensive care unit, hospital wards or emergency department. bAnticoagulation used twice daily if glomerular filtration rate (GFR) was greater than 30 mL/min, or once daily if GFR was 30 mL/min or less.