Table 1.

Baseline characteristics of included studies

Characteristics	Klok et al.	Cui et al.	Chen et al.	Tang et al.	Wang et al.	Helms et al.
Sample size	184	81	25	449	1026	150
Study design	Multi-center, retrospective study	Single-center retrospective study	Single-center, retrospective study	Retrospective analysis	Multi-center, retrospective study	Multi-center, prospective cohort
Study population	Severely ill COVID-19 patients admitted to the ICU	Severely ill COVID-19 patients admitted to the ICU	Hospitalized COVID-19 patients who underwent CTPA	Hospitalized, severely ill COVID-19 patients	Hospitalized COVID-19 patients	Severely ill, admitted to ICU
Age in years (mean)	64	60	Not reported	65.1 ± 12.0	42 for Padua score < 4 and 52 for score of ≥ 4	63 (median)
Male sex (%)	139 (76%)	37 (46%)	Not reported	268 (60%)	Not reported	122 (81.3)
Prophylaxis for VTE	All patients received at least standard doses of thromboprophylaxis Prophylaxis options: LMWH nadroparin 2850 IU/day > 100 kg = LMWH nadroparin 5700 IU/day Therapeutic anticoagulation: 17 (9.2%) on admission	None	20 pts. treated with LMWH 0.6 mg/kg every 12 h	• 94/99 patients received LMWH (40–60 mg/day) for 7 days or longer	10 (7%) of 140 patients for whom anticoagulation data were available had received anticoagulant drugs during hospitalization (nine received heparin and one received rivaroxaban)	Low molecular weight heparin 4000 UI/day or if contra-indicated, unfractionated heparin at 5–8 U/kg/h 105 (70%) prophylactic dosing 45 (30%) therapeutic dosing