Table 2

- The main characteristics of the included studies.

Study name, author, year and countryTotal number of patientsMalesMean ageNo anticoagulation groupProphylactic anticoagulation
1. D-dimer-driven anticoagulation reduces mortality in intubated COVID-19 patients: A cohort study with a propensity matched analysis (Tassiopoulos et al, 2021, USA)2919514159.50104
2. Preliminary experience with low molecular weight heparin strategy in COVID-19 patients (Paolisso et al, 2020, USA)304506874 361
3. Therapeutic versus prophylactic anticoagulation for severe COVID-19: A randomized phase II clinical trial (HESACOVID) (Lemos et al, 2020, Iran)31562325620220
4. Higher anticoagulation targets and risk of thrombotic events in severe COVID-19 patients: bi-center cohort study (Helms 2020, France)32179130620108
5. Optimizing management to reduce the mortality of COVID-19: Experience from a designated hospital for severely and critically Ill patients in China (Zhu 2021, China)3322121047340220
6. Empiric use of anticoagulation in hospitalized patients with COVID-19: a propensity score-matched study of risk and benefits (Yu et al, 2021, USA)342356060NA115
7. Beneficial effects of intermediate dosage of anticoagulation treatment on the prognosis of hospitalized covid 19 patients. (Poulakou, 2021, Greece)351212126
8. Effect of intermediate-dose vs standard-dose prophylactic anticoagulation on thrombotic events ECMO or mortality among patients with covid-19 admitted to the intensive care unit (Sadeghipour et al, 2021, Iran)36222117119NA220
9. Intermediate dose anticoagulation aspirin and in-hospital mortality in covid 19: A propensity score-matched analysis (Meizlish et al, 2021, USA)3753110414546536
10. Therapeutic anticoagulation with Heparin in critically ill patients with covid-19 (Goliggher et al, 2021, United Kingdom, USA, Canada, Brazil)38200567200NA70
11. Clinical presentation, course, and risk factors associated with mortality in a severe outbreak of covid-19 in Rhode Island, USA, April-June 2020 (Atalla et al, 2020, USA)39NA18NA73627
12. Early initiation of prophylactic anticoagulation for prevention of Coronavisrus disease 2019 mortality in patients admitted to the hospital in the United States: cochort study (Rentsch et al, 2021, USA)40NA678NA961395
USA: United States of America, Yrs: years, NA: not available