Risk of venous thromboembolism in patients with COVID-19: A systematic review and meta-analysis

Res Pract Thromb Haemost. 2020 Sep 25;4(7):1178-1191. doi: 10.1002/rth2.12439. Online ahead of print.


Background: Venous thromboembolism (VTE) is frequently observed in patients with coronavirus disease 2019 (COVID-19). However, reported VTE-rates differ substantially.

Objectives: We aimed at evaluating available data and estimating the prevalence of VTE in COVID-19 patients.

Methods: We conducted a systematic literature search (MEDLINE, EMBASE, WHO COVID-19 database) to identify studies reporting VTE-rates in COVID-19 patients. Studies with suspected high risk of bias were excluded from quantitative synthesis. Pooled outcome rates were obtained within a random effects meta-analysis. Subgroup analyses were performed for different settings (intensive care unit (ICU) vs. non-ICU hospitalization and screening vs. no screening) and the association of D-dimer levels and VTE-risk was explored.

Results: Eighty-six studies (33,970 patients) were identified and 66 (28,173 patients, mean age: 62.6 years, 60% men, 20% ICU-patients) were included in quantitative analysis. The overall VTE-prevalence estimate was 14.1% (95%CI 11.6-16.9), 40.3% (95%CI 27.0-54.3) with ultrasound-screening and 9.5% (95%CI 7.5-11.7) without screening. Subgroup analysis revealed high heterogeneity, with a VTE-prevalence of 7.9% (95%CI 5.1-11.2) in non-ICU and 22.7% (95%CI 18.1-27.6) in ICU patients. Prevalence of pulmonary embolism (PE) in non-ICU and ICU patients was 3.5% (95%CI 2.2-5.1) and 13.7% (95%CI 10.0-17.9). Patients developing VTE had higher D-dimer levels (weighted mean difference 3.26 µg/ml (95%CI 2.76-3.77) than non-VTE patients.

Conclusion: VTE occurs in 22.7% of patients with COVID-19 in the ICU, but VTE risk is also increased in non-ICU hospitalized patients. Patients developing VTE had higher D-dimer levels. Studies evaluating thromboprophylaxis strategies in patients with COVID-19 are needed to improve prevention of VTE.

Keywords: COVID‐19; Prevalence; Pulmonary Embolism; Severe Acute Respiratory Syndrome Coronavirus 2; Venous Thromboembolism.