Venous Thromboembolism Rates in Hospitalized Patients With COVID-19 Examined

A lack of rigorous study on venous thromboembolism incidence in hospitalized patients with COVID-19 means there are more questions than answers for long-term clinical implications.

Nearly 1 in 6 patients hospitalized with coronavirus disease 2019 (COVID-19) experience incident venous thromboembolism (VTE); however, the lack of rigorous study on VTE incidence in this population prevents understanding of the long-term clinical implications, according to study results published in CHEST.

Investigators conducted a systematic review and meta-analysis of 49 observational studies published between January 2020 and July 2020 that evaluated the incidence of VTE and/or bleeding in hospitalized patients with confirmed or probable COVID-19. The primary outcome was incidence of nonfatal or fatal VTE diagnoses during hospitalization for COVID-19. Bleeding during COVID-19-related hospitalization was included as a secondary outcome.

The total pooled sample size for the meta-analysis included 18,093 patients with reported information related to VTE, 1273 of whom experienced a VTE. Another pooled sample of 1411 patients with information related to bleeding included 148 patients who experienced a bleeding event during hospitalization.

The overall pooled incidence of VTE was 17% (95% CI, 13.4%-20.9%), compared with a pooled incidence of deep-vein thrombosis (DVT) of 12.1% (95% CI, 8.4%-16.4%) and a pooled incidence for pulmonary embolism (PE) of 7.1% (95% CI, 5.3%-9.1%). Pooled incidences for bleeding and major bleeding were 7.8% (95% CI, 2.6%-15.3%) and 3.9% (95% CI, 1.2%-7.9%), respectively.

VTE incidence was higher when examined by screening compared with clinical diagnosis (33.1% vs 9.8%; P <.0001). Higher incidence rates of VTE were found among patients in the intensive care unit compared with patients in the ward (27.9% vs 7.1%; P <.0001), and in prospective studies compared with retrospective studies (25.5% vs. 12.4%; P <.0001). After the exclusion of catheter-associated thrombosis/isolated distal DVTs, combined DVT incidence estimate was 6.2%. After excluding those with isolated subsegmental PEs, pooled PE incidence was 5.5% (P =.02).

The highest pooled incidence estimate of bleeding was found in patients who received intermediate- or full-dose anticoagulation vs standard dose or no thromboprophylaxis (21.4% vs 4.7% vs 4.4%, respectively; P <.001) and the lowest in the only prospective study that examined bleeding events (2.7% vs 9.4% for retrospective; P <.001).

Limitations of this analysis included the lack of individual patient data, the possibility of missing or unreported data from individual studies, as well as the lack of assessment of arterial thrombotic events.

”Additional studies are required to understand the utility of more potent antithrombotic or immunomodulatory therapies to safely mitigate the risk of thrombotic events, and mortality” in this vulnerable patient population, the researchers concluded.

Disclosure: One study author declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.


Jiménez D, García-Sanchez A, Rali P, et al. Incidence of venous thromboembolism and bleeding among hospitalized patients with COVID-19: a systematic review and meta-analysis. Published online November 17, 2020. CHEST. doi:10.1016/j.chest.2020.11.005