Table 4 Characteristics of retrospective COVID-19 studies on venous thromboembolism incidence rate and predictors

Cohen et al.

United States

Retrospective, March 1st to April 27th, 2020

9407

2.9% (2.4% in medical ward and 4.9% in ICU)

Multivariate analysis

For VTE or mortality:

1.Advanced age

2.Increasing Charlson Comorbidity Index

3.History of cardiovascular disease

4.ICU level of care, and

5.Elevated maximum D-dimer with a cutoff at least four times the upper limit of normal

Dalager- Pedersen et al.

Denmark

Retrospective, January 27th to June 1st, 2020

1540

5% VTE (both ICU and general ward)

30-day absolute risks

This Study compared COVID-19 and non-COVID-19 patients showed COVID-19 patients had a higher risk of VTE

Freund et al.

France, Spain, Belgium, Italy, Chile, Canada

Retrospective, February 1st to April 10th, 2020

974

15% (only PE, DVT not studied)

Multivariable binary logistic regression

1. Male gender

2. Age > 48

3. Heart rate

4. Prior history of VTEs

5. Clinical signs of DVT

6. Recent immobilization

Mei et al.

China

Retrospective, January 1st to March 23rd, 2020

616

2% VTE (DVT and/or PE)

χ² test, Fisher exact test, t test, and Mann–Whitney U test

This study compared Padua score in COVID-19 pneumonia and community-acquired pneumonia

Poissy et al.

France

Retrospective case series, February 27th to March 31st, 2020

196 (ICU patients only)

6.1% (PE only)

Simple descriptive analysis

None

Rieder et al.

China

Retrospective, March 26th to April 20th, 2020

49

6.1%

Spearman test

The level of D-dimers at hospital admission and the maximum level during follow-up were correlated with days at the hospital, days in ICU, days on non-invasive ventilation, or days on invasive ventilation